1773 lines
44 KiB
C
1773 lines
44 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* The Internet Protocol (IP) output module.
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*
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* Authors: Ross Biro
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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* Donald Becker, <becker@super.org>
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* Alan Cox, <Alan.Cox@linux.org>
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* Richard Underwood
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* Stefan Becker, <stefanb@yello.ping.de>
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* Jorge Cwik, <jorge@laser.satlink.net>
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* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
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* Hirokazu Takahashi, <taka@valinux.co.jp>
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*
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* See ip_input.c for original log
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*
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* Fixes:
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* Alan Cox : Missing nonblock feature in ip_build_xmit.
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* Mike Kilburn : htons() missing in ip_build_xmit.
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* Bradford Johnson: Fix faulty handling of some frames when
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* no route is found.
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* Alexander Demenshin: Missing sk/skb free in ip_queue_xmit
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* (in case if packet not accepted by
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* output firewall rules)
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* Mike McLagan : Routing by source
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* Alexey Kuznetsov: use new route cache
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* Andi Kleen: Fix broken PMTU recovery and remove
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* some redundant tests.
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* Vitaly E. Lavrov : Transparent proxy revived after year coma.
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* Andi Kleen : Replace ip_reply with ip_send_reply.
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* Andi Kleen : Split fast and slow ip_build_xmit path
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* for decreased register pressure on x86
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* and more readability.
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* Marc Boucher : When call_out_firewall returns FW_QUEUE,
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* silently drop skb instead of failing with -EPERM.
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* Detlev Wengorz : Copy protocol for fragments.
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* Hirokazu Takahashi: HW checksumming for outgoing UDP
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* datagrams.
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* Hirokazu Takahashi: sendfile() on UDP works now.
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*/
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#include <linux/uaccess.h>
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/highmem.h>
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#include <linux/slab.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/in.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <linux/proc_fs.h>
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#include <linux/stat.h>
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#include <linux/init.h>
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#include <net/snmp.h>
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#include <net/ip.h>
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#include <net/protocol.h>
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#include <net/route.h>
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#include <net/xfrm.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/arp.h>
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#include <net/icmp.h>
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#include <net/checksum.h>
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#include <net/inetpeer.h>
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#include <net/inet_ecn.h>
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#include <net/lwtunnel.h>
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#include <linux/bpf-cgroup.h>
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#include <linux/igmp.h>
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#include <linux/netfilter_ipv4.h>
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#include <linux/netfilter_bridge.h>
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#include <linux/netlink.h>
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#include <linux/tcp.h>
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static int
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ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
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unsigned int mtu,
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int (*output)(struct net *, struct sock *, struct sk_buff *));
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/* Generate a checksum for an outgoing IP datagram. */
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void ip_send_check(struct iphdr *iph)
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{
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iph->check = 0;
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iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl);
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}
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EXPORT_SYMBOL(ip_send_check);
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int __ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct iphdr *iph = ip_hdr(skb);
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iph_set_totlen(iph, skb->len);
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ip_send_check(iph);
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/* if egress device is enslaved to an L3 master device pass the
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* skb to its handler for processing
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*/
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skb = l3mdev_ip_out(sk, skb);
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if (unlikely(!skb))
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return 0;
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skb->protocol = htons(ETH_P_IP);
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return nf_hook(NFPROTO_IPV4, NF_INET_LOCAL_OUT,
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net, sk, skb, NULL, skb_dst(skb)->dev,
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dst_output);
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}
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int ip_local_out(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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int err;
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err = __ip_local_out(net, sk, skb);
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if (likely(err == 1))
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err = dst_output(net, sk, skb);
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return err;
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}
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EXPORT_SYMBOL_GPL(ip_local_out);
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static inline int ip_select_ttl(const struct inet_sock *inet,
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const struct dst_entry *dst)
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{
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int ttl = inet->uc_ttl;
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if (ttl < 0)
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ttl = ip4_dst_hoplimit(dst);
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return ttl;
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}
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/*
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* Add an ip header to a skbuff and send it out.
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*
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*/
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int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
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__be32 saddr, __be32 daddr, struct ip_options_rcu *opt,
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u8 tos)
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{
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const struct inet_sock *inet = inet_sk(sk);
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struct rtable *rt = skb_rtable(skb);
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struct net *net = sock_net(sk);
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struct iphdr *iph;
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/* Build the IP header. */
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skb_push(skb, sizeof(struct iphdr) + (opt ? opt->opt.optlen : 0));
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skb_reset_network_header(skb);
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iph = ip_hdr(skb);
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iph->version = 4;
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iph->ihl = 5;
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iph->tos = tos;
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iph->ttl = ip_select_ttl(inet, &rt->dst);
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iph->daddr = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
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iph->saddr = saddr;
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iph->protocol = sk->sk_protocol;
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/* Do not bother generating IPID for small packets (eg SYNACK) */
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if (skb->len <= IPV4_MIN_MTU || ip_dont_fragment(sk, &rt->dst)) {
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iph->frag_off = htons(IP_DF);
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iph->id = 0;
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} else {
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iph->frag_off = 0;
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/* TCP packets here are SYNACK with fat IPv4/TCP options.
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* Avoid using the hashed IP ident generator.
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*/
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if (sk->sk_protocol == IPPROTO_TCP)
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iph->id = (__force __be16)get_random_u16();
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else
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__ip_select_ident(net, iph, 1);
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}
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if (opt && opt->opt.optlen) {
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iph->ihl += opt->opt.optlen>>2;
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ip_options_build(skb, &opt->opt, daddr, rt);
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}
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skb->priority = sk->sk_priority;
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if (!skb->mark)
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skb->mark = sk->sk_mark;
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/* Send it out. */
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return ip_local_out(net, skb->sk, skb);
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}
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EXPORT_SYMBOL_GPL(ip_build_and_send_pkt);
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static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct dst_entry *dst = skb_dst(skb);
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struct rtable *rt = (struct rtable *)dst;
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struct net_device *dev = dst->dev;
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unsigned int hh_len = LL_RESERVED_SPACE(dev);
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struct neighbour *neigh;
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bool is_v6gw = false;
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if (rt->rt_type == RTN_MULTICAST) {
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTMCAST, skb->len);
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} else if (rt->rt_type == RTN_BROADCAST)
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUTBCAST, skb->len);
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if (unlikely(skb_headroom(skb) < hh_len && dev->header_ops)) {
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skb = skb_expand_head(skb, hh_len);
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if (!skb)
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return -ENOMEM;
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}
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if (lwtunnel_xmit_redirect(dst->lwtstate)) {
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int res = lwtunnel_xmit(skb);
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if (res < 0 || res == LWTUNNEL_XMIT_DONE)
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return res;
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}
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rcu_read_lock();
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neigh = ip_neigh_for_gw(rt, skb, &is_v6gw);
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if (!IS_ERR(neigh)) {
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int res;
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sock_confirm_neigh(skb, neigh);
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/* if crossing protocols, can not use the cached header */
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res = neigh_output(neigh, skb, is_v6gw);
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rcu_read_unlock();
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return res;
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}
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rcu_read_unlock();
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net_dbg_ratelimited("%s: No header cache and no neighbour!\n",
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__func__);
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kfree_skb_reason(skb, SKB_DROP_REASON_NEIGH_CREATEFAIL);
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return -EINVAL;
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}
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static int ip_finish_output_gso(struct net *net, struct sock *sk,
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struct sk_buff *skb, unsigned int mtu)
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{
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struct sk_buff *segs, *nskb;
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netdev_features_t features;
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int ret = 0;
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/* common case: seglen is <= mtu
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*/
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if (skb_gso_validate_network_len(skb, mtu))
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return ip_finish_output2(net, sk, skb);
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/* Slowpath - GSO segment length exceeds the egress MTU.
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*
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* This can happen in several cases:
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* - Forwarding of a TCP GRO skb, when DF flag is not set.
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* - Forwarding of an skb that arrived on a virtualization interface
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* (virtio-net/vhost/tap) with TSO/GSO size set by other network
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* stack.
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* - Local GSO skb transmitted on an NETIF_F_TSO tunnel stacked over an
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* interface with a smaller MTU.
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* - Arriving GRO skb (or GSO skb in a virtualized environment) that is
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* bridged to a NETIF_F_TSO tunnel stacked over an interface with an
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* insufficient MTU.
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*/
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features = netif_skb_features(skb);
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BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
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segs = skb_gso_segment(skb, features & ~NETIF_F_GSO_MASK);
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if (IS_ERR_OR_NULL(segs)) {
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kfree_skb(skb);
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return -ENOMEM;
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}
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consume_skb(skb);
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skb_list_walk_safe(segs, segs, nskb) {
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int err;
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skb_mark_not_on_list(segs);
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err = ip_fragment(net, sk, segs, mtu, ip_finish_output2);
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if (err && ret == 0)
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ret = err;
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}
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return ret;
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}
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static int __ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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unsigned int mtu;
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#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
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/* Policy lookup after SNAT yielded a new policy */
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if (skb_dst(skb)->xfrm) {
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IPCB(skb)->flags |= IPSKB_REROUTED;
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return dst_output(net, sk, skb);
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}
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#endif
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mtu = ip_skb_dst_mtu(sk, skb);
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if (skb_is_gso(skb))
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return ip_finish_output_gso(net, sk, skb, mtu);
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if (skb->len > mtu || IPCB(skb)->frag_max_size)
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return ip_fragment(net, sk, skb, mtu, ip_finish_output2);
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return ip_finish_output2(net, sk, skb);
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}
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static int ip_finish_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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int ret;
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ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
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switch (ret) {
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case NET_XMIT_SUCCESS:
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return __ip_finish_output(net, sk, skb);
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case NET_XMIT_CN:
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return __ip_finish_output(net, sk, skb) ? : ret;
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default:
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kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
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return ret;
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}
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}
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static int ip_mc_finish_output(struct net *net, struct sock *sk,
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struct sk_buff *skb)
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{
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struct rtable *new_rt;
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bool do_cn = false;
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int ret, err;
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ret = BPF_CGROUP_RUN_PROG_INET_EGRESS(sk, skb);
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switch (ret) {
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case NET_XMIT_CN:
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do_cn = true;
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fallthrough;
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case NET_XMIT_SUCCESS:
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break;
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default:
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kfree_skb_reason(skb, SKB_DROP_REASON_BPF_CGROUP_EGRESS);
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return ret;
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}
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/* Reset rt_iif so that inet_iif() will return skb->skb_iif. Setting
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* this to non-zero causes ipi_ifindex in in_pktinfo to be overwritten,
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* see ipv4_pktinfo_prepare().
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*/
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new_rt = rt_dst_clone(net->loopback_dev, skb_rtable(skb));
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if (new_rt) {
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new_rt->rt_iif = 0;
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skb_dst_drop(skb);
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skb_dst_set(skb, &new_rt->dst);
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}
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err = dev_loopback_xmit(net, sk, skb);
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return (do_cn && err) ? ret : err;
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}
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int ip_mc_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct rtable *rt = skb_rtable(skb);
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struct net_device *dev = rt->dst.dev;
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/*
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* If the indicated interface is up and running, send the packet.
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*/
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
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skb->dev = dev;
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skb->protocol = htons(ETH_P_IP);
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/*
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* Multicasts are looped back for other local users
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*/
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if (rt->rt_flags&RTCF_MULTICAST) {
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if (sk_mc_loop(sk)
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#ifdef CONFIG_IP_MROUTE
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/* Small optimization: do not loopback not local frames,
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which returned after forwarding; they will be dropped
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by ip_mr_input in any case.
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Note, that local frames are looped back to be delivered
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to local recipients.
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This check is duplicated in ip_mr_input at the moment.
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*/
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&&
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((rt->rt_flags & RTCF_LOCAL) ||
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!(IPCB(skb)->flags & IPSKB_FORWARDED))
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#endif
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) {
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struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
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if (newskb)
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NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
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net, sk, newskb, NULL, newskb->dev,
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ip_mc_finish_output);
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}
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/* Multicasts with ttl 0 must not go beyond the host */
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if (ip_hdr(skb)->ttl == 0) {
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kfree_skb(skb);
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return 0;
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}
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}
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if (rt->rt_flags&RTCF_BROADCAST) {
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struct sk_buff *newskb = skb_clone(skb, GFP_ATOMIC);
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if (newskb)
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NF_HOOK(NFPROTO_IPV4, NF_INET_POST_ROUTING,
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net, sk, newskb, NULL, newskb->dev,
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ip_mc_finish_output);
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}
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return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
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net, sk, skb, NULL, skb->dev,
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ip_finish_output,
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!(IPCB(skb)->flags & IPSKB_REROUTED));
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}
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int ip_output(struct net *net, struct sock *sk, struct sk_buff *skb)
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{
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struct net_device *dev = skb_dst(skb)->dev, *indev = skb->dev;
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IP_UPD_PO_STATS(net, IPSTATS_MIB_OUT, skb->len);
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skb->dev = dev;
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skb->protocol = htons(ETH_P_IP);
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return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
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net, sk, skb, indev, dev,
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ip_finish_output,
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!(IPCB(skb)->flags & IPSKB_REROUTED));
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}
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EXPORT_SYMBOL(ip_output);
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/*
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* copy saddr and daddr, possibly using 64bit load/stores
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* Equivalent to :
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* iph->saddr = fl4->saddr;
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* iph->daddr = fl4->daddr;
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*/
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static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
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{
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BUILD_BUG_ON(offsetof(typeof(*fl4), daddr) !=
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offsetof(typeof(*fl4), saddr) + sizeof(fl4->saddr));
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iph->saddr = fl4->saddr;
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iph->daddr = fl4->daddr;
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}
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/* Note: skb->sk can be different from sk, in case of tunnels */
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int __ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl,
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__u8 tos)
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{
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struct inet_sock *inet = inet_sk(sk);
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struct net *net = sock_net(sk);
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struct ip_options_rcu *inet_opt;
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struct flowi4 *fl4;
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struct rtable *rt;
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struct iphdr *iph;
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int res;
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/* Skip all of this if the packet is already routed,
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* f.e. by something like SCTP.
|
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*/
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rcu_read_lock();
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inet_opt = rcu_dereference(inet->inet_opt);
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fl4 = &fl->u.ip4;
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rt = skb_rtable(skb);
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if (rt)
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goto packet_routed;
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/* Make sure we can route this packet. */
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rt = (struct rtable *)__sk_dst_check(sk, 0);
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if (!rt) {
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__be32 daddr;
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/* Use correct destination address if we have options. */
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daddr = inet->inet_daddr;
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if (inet_opt && inet_opt->opt.srr)
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daddr = inet_opt->opt.faddr;
|
|
|
|
/* If this fails, retransmit mechanism of transport layer will
|
|
* keep trying until route appears or the connection times
|
|
* itself out.
|
|
*/
|
|
rt = ip_route_output_ports(net, fl4, sk,
|
|
daddr, inet->inet_saddr,
|
|
inet->inet_dport,
|
|
inet->inet_sport,
|
|
sk->sk_protocol,
|
|
RT_CONN_FLAGS_TOS(sk, tos),
|
|
sk->sk_bound_dev_if);
|
|
if (IS_ERR(rt))
|
|
goto no_route;
|
|
sk_setup_caps(sk, &rt->dst);
|
|
}
|
|
skb_dst_set_noref(skb, &rt->dst);
|
|
|
|
packet_routed:
|
|
if (inet_opt && inet_opt->opt.is_strictroute && rt->rt_uses_gateway)
|
|
goto no_route;
|
|
|
|
/* OK, we know where to send it, allocate and build IP header. */
|
|
skb_push(skb, sizeof(struct iphdr) + (inet_opt ? inet_opt->opt.optlen : 0));
|
|
skb_reset_network_header(skb);
|
|
iph = ip_hdr(skb);
|
|
*((__be16 *)iph) = htons((4 << 12) | (5 << 8) | (tos & 0xff));
|
|
if (ip_dont_fragment(sk, &rt->dst) && !skb->ignore_df)
|
|
iph->frag_off = htons(IP_DF);
|
|
else
|
|
iph->frag_off = 0;
|
|
iph->ttl = ip_select_ttl(inet, &rt->dst);
|
|
iph->protocol = sk->sk_protocol;
|
|
ip_copy_addrs(iph, fl4);
|
|
|
|
/* Transport layer set skb->h.foo itself. */
|
|
|
|
if (inet_opt && inet_opt->opt.optlen) {
|
|
iph->ihl += inet_opt->opt.optlen >> 2;
|
|
ip_options_build(skb, &inet_opt->opt, inet->inet_daddr, rt);
|
|
}
|
|
|
|
ip_select_ident_segs(net, skb, sk,
|
|
skb_shinfo(skb)->gso_segs ?: 1);
|
|
|
|
/* TODO : should we use skb->sk here instead of sk ? */
|
|
skb->priority = sk->sk_priority;
|
|
skb->mark = sk->sk_mark;
|
|
|
|
res = ip_local_out(net, sk, skb);
|
|
rcu_read_unlock();
|
|
return res;
|
|
|
|
no_route:
|
|
rcu_read_unlock();
|
|
IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
|
|
kfree_skb_reason(skb, SKB_DROP_REASON_IP_OUTNOROUTES);
|
|
return -EHOSTUNREACH;
|
|
}
|
|
EXPORT_SYMBOL(__ip_queue_xmit);
|
|
|
|
int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
|
|
{
|
|
return __ip_queue_xmit(sk, skb, fl, inet_sk(sk)->tos);
|
|
}
|
|
EXPORT_SYMBOL(ip_queue_xmit);
|
|
|
|
static void ip_copy_metadata(struct sk_buff *to, struct sk_buff *from)
|
|
{
|
|
to->pkt_type = from->pkt_type;
|
|
to->priority = from->priority;
|
|
to->protocol = from->protocol;
|
|
to->skb_iif = from->skb_iif;
|
|
skb_dst_drop(to);
|
|
skb_dst_copy(to, from);
|
|
to->dev = from->dev;
|
|
to->mark = from->mark;
|
|
|
|
skb_copy_hash(to, from);
|
|
|
|
#ifdef CONFIG_NET_SCHED
|
|
to->tc_index = from->tc_index;
|
|
#endif
|
|
nf_copy(to, from);
|
|
skb_ext_copy(to, from);
|
|
#if IS_ENABLED(CONFIG_IP_VS)
|
|
to->ipvs_property = from->ipvs_property;
|
|
#endif
|
|
skb_copy_secmark(to, from);
|
|
}
|
|
|
|
static int ip_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
|
|
unsigned int mtu,
|
|
int (*output)(struct net *, struct sock *, struct sk_buff *))
|
|
{
|
|
struct iphdr *iph = ip_hdr(skb);
|
|
|
|
if ((iph->frag_off & htons(IP_DF)) == 0)
|
|
return ip_do_fragment(net, sk, skb, output);
|
|
|
|
if (unlikely(!skb->ignore_df ||
|
|
(IPCB(skb)->frag_max_size &&
|
|
IPCB(skb)->frag_max_size > mtu))) {
|
|
IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
|
|
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED,
|
|
htonl(mtu));
|
|
kfree_skb(skb);
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
return ip_do_fragment(net, sk, skb, output);
|
|
}
|
|
|
|
void ip_fraglist_init(struct sk_buff *skb, struct iphdr *iph,
|
|
unsigned int hlen, struct ip_fraglist_iter *iter)
|
|
{
|
|
unsigned int first_len = skb_pagelen(skb);
|
|
|
|
iter->frag = skb_shinfo(skb)->frag_list;
|
|
skb_frag_list_init(skb);
|
|
|
|
iter->offset = 0;
|
|
iter->iph = iph;
|
|
iter->hlen = hlen;
|
|
|
|
skb->data_len = first_len - skb_headlen(skb);
|
|
skb->len = first_len;
|
|
iph->tot_len = htons(first_len);
|
|
iph->frag_off = htons(IP_MF);
|
|
ip_send_check(iph);
|
|
}
|
|
EXPORT_SYMBOL(ip_fraglist_init);
|
|
|
|
void ip_fraglist_prepare(struct sk_buff *skb, struct ip_fraglist_iter *iter)
|
|
{
|
|
unsigned int hlen = iter->hlen;
|
|
struct iphdr *iph = iter->iph;
|
|
struct sk_buff *frag;
|
|
|
|
frag = iter->frag;
|
|
frag->ip_summed = CHECKSUM_NONE;
|
|
skb_reset_transport_header(frag);
|
|
__skb_push(frag, hlen);
|
|
skb_reset_network_header(frag);
|
|
memcpy(skb_network_header(frag), iph, hlen);
|
|
iter->iph = ip_hdr(frag);
|
|
iph = iter->iph;
|
|
iph->tot_len = htons(frag->len);
|
|
ip_copy_metadata(frag, skb);
|
|
iter->offset += skb->len - hlen;
|
|
iph->frag_off = htons(iter->offset >> 3);
|
|
if (frag->next)
|
|
iph->frag_off |= htons(IP_MF);
|
|
/* Ready, complete checksum */
|
|
ip_send_check(iph);
|
|
}
|
|
EXPORT_SYMBOL(ip_fraglist_prepare);
|
|
|
|
void ip_frag_init(struct sk_buff *skb, unsigned int hlen,
|
|
unsigned int ll_rs, unsigned int mtu, bool DF,
|
|
struct ip_frag_state *state)
|
|
{
|
|
struct iphdr *iph = ip_hdr(skb);
|
|
|
|
state->DF = DF;
|
|
state->hlen = hlen;
|
|
state->ll_rs = ll_rs;
|
|
state->mtu = mtu;
|
|
|
|
state->left = skb->len - hlen; /* Space per frame */
|
|
state->ptr = hlen; /* Where to start from */
|
|
|
|
state->offset = (ntohs(iph->frag_off) & IP_OFFSET) << 3;
|
|
state->not_last_frag = iph->frag_off & htons(IP_MF);
|
|
}
|
|
EXPORT_SYMBOL(ip_frag_init);
|
|
|
|
static void ip_frag_ipcb(struct sk_buff *from, struct sk_buff *to,
|
|
bool first_frag)
|
|
{
|
|
/* Copy the flags to each fragment. */
|
|
IPCB(to)->flags = IPCB(from)->flags;
|
|
|
|
/* ANK: dirty, but effective trick. Upgrade options only if
|
|
* the segment to be fragmented was THE FIRST (otherwise,
|
|
* options are already fixed) and make it ONCE
|
|
* on the initial skb, so that all the following fragments
|
|
* will inherit fixed options.
|
|
*/
|
|
if (first_frag)
|
|
ip_options_fragment(from);
|
|
}
|
|
|
|
struct sk_buff *ip_frag_next(struct sk_buff *skb, struct ip_frag_state *state)
|
|
{
|
|
unsigned int len = state->left;
|
|
struct sk_buff *skb2;
|
|
struct iphdr *iph;
|
|
|
|
/* IF: it doesn't fit, use 'mtu' - the data space left */
|
|
if (len > state->mtu)
|
|
len = state->mtu;
|
|
/* IF: we are not sending up to and including the packet end
|
|
then align the next start on an eight byte boundary */
|
|
if (len < state->left) {
|
|
len &= ~7;
|
|
}
|
|
|
|
/* Allocate buffer */
|
|
skb2 = alloc_skb(len + state->hlen + state->ll_rs, GFP_ATOMIC);
|
|
if (!skb2)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/*
|
|
* Set up data on packet
|
|
*/
|
|
|
|
ip_copy_metadata(skb2, skb);
|
|
skb_reserve(skb2, state->ll_rs);
|
|
skb_put(skb2, len + state->hlen);
|
|
skb_reset_network_header(skb2);
|
|
skb2->transport_header = skb2->network_header + state->hlen;
|
|
|
|
/*
|
|
* Charge the memory for the fragment to any owner
|
|
* it might possess
|
|
*/
|
|
|
|
if (skb->sk)
|
|
skb_set_owner_w(skb2, skb->sk);
|
|
|
|
/*
|
|
* Copy the packet header into the new buffer.
|
|
*/
|
|
|
|
skb_copy_from_linear_data(skb, skb_network_header(skb2), state->hlen);
|
|
|
|
/*
|
|
* Copy a block of the IP datagram.
|
|
*/
|
|
if (skb_copy_bits(skb, state->ptr, skb_transport_header(skb2), len))
|
|
BUG();
|
|
state->left -= len;
|
|
|
|
/*
|
|
* Fill in the new header fields.
|
|
*/
|
|
iph = ip_hdr(skb2);
|
|
iph->frag_off = htons((state->offset >> 3));
|
|
if (state->DF)
|
|
iph->frag_off |= htons(IP_DF);
|
|
|
|
/*
|
|
* Added AC : If we are fragmenting a fragment that's not the
|
|
* last fragment then keep MF on each bit
|
|
*/
|
|
if (state->left > 0 || state->not_last_frag)
|
|
iph->frag_off |= htons(IP_MF);
|
|
state->ptr += len;
|
|
state->offset += len;
|
|
|
|
iph->tot_len = htons(len + state->hlen);
|
|
|
|
ip_send_check(iph);
|
|
|
|
return skb2;
|
|
}
|
|
EXPORT_SYMBOL(ip_frag_next);
|
|
|
|
/*
|
|
* This IP datagram is too large to be sent in one piece. Break it up into
|
|
* smaller pieces (each of size equal to IP header plus
|
|
* a block of the data of the original IP data part) that will yet fit in a
|
|
* single device frame, and queue such a frame for sending.
|
|
*/
|
|
|
|
int ip_do_fragment(struct net *net, struct sock *sk, struct sk_buff *skb,
|
|
int (*output)(struct net *, struct sock *, struct sk_buff *))
|
|
{
|
|
struct iphdr *iph;
|
|
struct sk_buff *skb2;
|
|
bool mono_delivery_time = skb->mono_delivery_time;
|
|
struct rtable *rt = skb_rtable(skb);
|
|
unsigned int mtu, hlen, ll_rs;
|
|
struct ip_fraglist_iter iter;
|
|
ktime_t tstamp = skb->tstamp;
|
|
struct ip_frag_state state;
|
|
int err = 0;
|
|
|
|
/* for offloaded checksums cleanup checksum before fragmentation */
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL &&
|
|
(err = skb_checksum_help(skb)))
|
|
goto fail;
|
|
|
|
/*
|
|
* Point into the IP datagram header.
|
|
*/
|
|
|
|
iph = ip_hdr(skb);
|
|
|
|
mtu = ip_skb_dst_mtu(sk, skb);
|
|
if (IPCB(skb)->frag_max_size && IPCB(skb)->frag_max_size < mtu)
|
|
mtu = IPCB(skb)->frag_max_size;
|
|
|
|
/*
|
|
* Setup starting values.
|
|
*/
|
|
|
|
hlen = iph->ihl * 4;
|
|
mtu = mtu - hlen; /* Size of data space */
|
|
IPCB(skb)->flags |= IPSKB_FRAG_COMPLETE;
|
|
ll_rs = LL_RESERVED_SPACE(rt->dst.dev);
|
|
|
|
/* When frag_list is given, use it. First, check its validity:
|
|
* some transformers could create wrong frag_list or break existing
|
|
* one, it is not prohibited. In this case fall back to copying.
|
|
*
|
|
* LATER: this step can be merged to real generation of fragments,
|
|
* we can switch to copy when see the first bad fragment.
|
|
*/
|
|
if (skb_has_frag_list(skb)) {
|
|
struct sk_buff *frag, *frag2;
|
|
unsigned int first_len = skb_pagelen(skb);
|
|
|
|
if (first_len - hlen > mtu ||
|
|
((first_len - hlen) & 7) ||
|
|
ip_is_fragment(iph) ||
|
|
skb_cloned(skb) ||
|
|
skb_headroom(skb) < ll_rs)
|
|
goto slow_path;
|
|
|
|
skb_walk_frags(skb, frag) {
|
|
/* Correct geometry. */
|
|
if (frag->len > mtu ||
|
|
((frag->len & 7) && frag->next) ||
|
|
skb_headroom(frag) < hlen + ll_rs)
|
|
goto slow_path_clean;
|
|
|
|
/* Partially cloned skb? */
|
|
if (skb_shared(frag))
|
|
goto slow_path_clean;
|
|
|
|
BUG_ON(frag->sk);
|
|
if (skb->sk) {
|
|
frag->sk = skb->sk;
|
|
frag->destructor = sock_wfree;
|
|
}
|
|
skb->truesize -= frag->truesize;
|
|
}
|
|
|
|
/* Everything is OK. Generate! */
|
|
ip_fraglist_init(skb, iph, hlen, &iter);
|
|
|
|
for (;;) {
|
|
/* Prepare header of the next frame,
|
|
* before previous one went down. */
|
|
if (iter.frag) {
|
|
bool first_frag = (iter.offset == 0);
|
|
|
|
IPCB(iter.frag)->flags = IPCB(skb)->flags;
|
|
ip_fraglist_prepare(skb, &iter);
|
|
if (first_frag && IPCB(skb)->opt.optlen) {
|
|
/* ipcb->opt is not populated for frags
|
|
* coming from __ip_make_skb(),
|
|
* ip_options_fragment() needs optlen
|
|
*/
|
|
IPCB(iter.frag)->opt.optlen =
|
|
IPCB(skb)->opt.optlen;
|
|
ip_options_fragment(iter.frag);
|
|
ip_send_check(iter.iph);
|
|
}
|
|
}
|
|
|
|
skb_set_delivery_time(skb, tstamp, mono_delivery_time);
|
|
err = output(net, sk, skb);
|
|
|
|
if (!err)
|
|
IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES);
|
|
if (err || !iter.frag)
|
|
break;
|
|
|
|
skb = ip_fraglist_next(&iter);
|
|
}
|
|
|
|
if (err == 0) {
|
|
IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS);
|
|
return 0;
|
|
}
|
|
|
|
kfree_skb_list(iter.frag);
|
|
|
|
IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
|
|
return err;
|
|
|
|
slow_path_clean:
|
|
skb_walk_frags(skb, frag2) {
|
|
if (frag2 == frag)
|
|
break;
|
|
frag2->sk = NULL;
|
|
frag2->destructor = NULL;
|
|
skb->truesize += frag2->truesize;
|
|
}
|
|
}
|
|
|
|
slow_path:
|
|
/*
|
|
* Fragment the datagram.
|
|
*/
|
|
|
|
ip_frag_init(skb, hlen, ll_rs, mtu, IPCB(skb)->flags & IPSKB_FRAG_PMTU,
|
|
&state);
|
|
|
|
/*
|
|
* Keep copying data until we run out.
|
|
*/
|
|
|
|
while (state.left > 0) {
|
|
bool first_frag = (state.offset == 0);
|
|
|
|
skb2 = ip_frag_next(skb, &state);
|
|
if (IS_ERR(skb2)) {
|
|
err = PTR_ERR(skb2);
|
|
goto fail;
|
|
}
|
|
ip_frag_ipcb(skb, skb2, first_frag);
|
|
|
|
/*
|
|
* Put this fragment into the sending queue.
|
|
*/
|
|
skb_set_delivery_time(skb2, tstamp, mono_delivery_time);
|
|
err = output(net, sk, skb2);
|
|
if (err)
|
|
goto fail;
|
|
|
|
IP_INC_STATS(net, IPSTATS_MIB_FRAGCREATES);
|
|
}
|
|
consume_skb(skb);
|
|
IP_INC_STATS(net, IPSTATS_MIB_FRAGOKS);
|
|
return err;
|
|
|
|
fail:
|
|
kfree_skb(skb);
|
|
IP_INC_STATS(net, IPSTATS_MIB_FRAGFAILS);
|
|
return err;
|
|
}
|
|
EXPORT_SYMBOL(ip_do_fragment);
|
|
|
|
int
|
|
ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk_buff *skb)
|
|
{
|
|
struct msghdr *msg = from;
|
|
|
|
if (skb->ip_summed == CHECKSUM_PARTIAL) {
|
|
if (!copy_from_iter_full(to, len, &msg->msg_iter))
|
|
return -EFAULT;
|
|
} else {
|
|
__wsum csum = 0;
|
|
if (!csum_and_copy_from_iter_full(to, len, &csum, &msg->msg_iter))
|
|
return -EFAULT;
|
|
skb->csum = csum_block_add(skb->csum, csum, odd);
|
|
}
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(ip_generic_getfrag);
|
|
|
|
static inline __wsum
|
|
csum_page(struct page *page, int offset, int copy)
|
|
{
|
|
char *kaddr;
|
|
__wsum csum;
|
|
kaddr = kmap(page);
|
|
csum = csum_partial(kaddr + offset, copy, 0);
|
|
kunmap(page);
|
|
return csum;
|
|
}
|
|
|
|
static int __ip_append_data(struct sock *sk,
|
|
struct flowi4 *fl4,
|
|
struct sk_buff_head *queue,
|
|
struct inet_cork *cork,
|
|
struct page_frag *pfrag,
|
|
int getfrag(void *from, char *to, int offset,
|
|
int len, int odd, struct sk_buff *skb),
|
|
void *from, int length, int transhdrlen,
|
|
unsigned int flags)
|
|
{
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
struct ubuf_info *uarg = NULL;
|
|
struct sk_buff *skb;
|
|
struct ip_options *opt = cork->opt;
|
|
int hh_len;
|
|
int exthdrlen;
|
|
int mtu;
|
|
int copy;
|
|
int err;
|
|
int offset = 0;
|
|
bool zc = false;
|
|
unsigned int maxfraglen, fragheaderlen, maxnonfragsize;
|
|
int csummode = CHECKSUM_NONE;
|
|
struct rtable *rt = (struct rtable *)cork->dst;
|
|
unsigned int wmem_alloc_delta = 0;
|
|
bool paged, extra_uref = false;
|
|
u32 tskey = 0;
|
|
|
|
skb = skb_peek_tail(queue);
|
|
|
|
exthdrlen = !skb ? rt->dst.header_len : 0;
|
|
mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize;
|
|
paged = !!cork->gso_size;
|
|
|
|
if (cork->tx_flags & SKBTX_ANY_TSTAMP &&
|
|
sk->sk_tsflags & SOF_TIMESTAMPING_OPT_ID)
|
|
tskey = atomic_inc_return(&sk->sk_tskey) - 1;
|
|
|
|
hh_len = LL_RESERVED_SPACE(rt->dst.dev);
|
|
|
|
fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
|
|
maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
|
|
maxnonfragsize = ip_sk_ignore_df(sk) ? IP_MAX_MTU : mtu;
|
|
|
|
if (cork->length + length > maxnonfragsize - fragheaderlen) {
|
|
ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
|
|
mtu - (opt ? opt->optlen : 0));
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
/*
|
|
* transhdrlen > 0 means that this is the first fragment and we wish
|
|
* it won't be fragmented in the future.
|
|
*/
|
|
if (transhdrlen &&
|
|
length + fragheaderlen <= mtu &&
|
|
rt->dst.dev->features & (NETIF_F_HW_CSUM | NETIF_F_IP_CSUM) &&
|
|
(!(flags & MSG_MORE) || cork->gso_size) &&
|
|
(!exthdrlen || (rt->dst.dev->features & NETIF_F_HW_ESP_TX_CSUM)))
|
|
csummode = CHECKSUM_PARTIAL;
|
|
|
|
if ((flags & MSG_ZEROCOPY) && length) {
|
|
struct msghdr *msg = from;
|
|
|
|
if (getfrag == ip_generic_getfrag && msg->msg_ubuf) {
|
|
if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb))
|
|
return -EINVAL;
|
|
|
|
/* Leave uarg NULL if can't zerocopy, callers should
|
|
* be able to handle it.
|
|
*/
|
|
if ((rt->dst.dev->features & NETIF_F_SG) &&
|
|
csummode == CHECKSUM_PARTIAL) {
|
|
paged = true;
|
|
zc = true;
|
|
uarg = msg->msg_ubuf;
|
|
}
|
|
} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
|
|
uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));
|
|
if (!uarg)
|
|
return -ENOBUFS;
|
|
extra_uref = !skb_zcopy(skb); /* only ref on new uarg */
|
|
if (rt->dst.dev->features & NETIF_F_SG &&
|
|
csummode == CHECKSUM_PARTIAL) {
|
|
paged = true;
|
|
zc = true;
|
|
} else {
|
|
uarg_to_msgzc(uarg)->zerocopy = 0;
|
|
skb_zcopy_set(skb, uarg, &extra_uref);
|
|
}
|
|
}
|
|
}
|
|
|
|
cork->length += length;
|
|
|
|
/* So, what's going on in the loop below?
|
|
*
|
|
* We use calculated fragment length to generate chained skb,
|
|
* each of segments is IP fragment ready for sending to network after
|
|
* adding appropriate IP header.
|
|
*/
|
|
|
|
if (!skb)
|
|
goto alloc_new_skb;
|
|
|
|
while (length > 0) {
|
|
/* Check if the remaining data fits into current packet. */
|
|
copy = mtu - skb->len;
|
|
if (copy < length)
|
|
copy = maxfraglen - skb->len;
|
|
if (copy <= 0) {
|
|
char *data;
|
|
unsigned int datalen;
|
|
unsigned int fraglen;
|
|
unsigned int fraggap;
|
|
unsigned int alloclen, alloc_extra;
|
|
unsigned int pagedlen;
|
|
struct sk_buff *skb_prev;
|
|
alloc_new_skb:
|
|
skb_prev = skb;
|
|
if (skb_prev)
|
|
fraggap = skb_prev->len - maxfraglen;
|
|
else
|
|
fraggap = 0;
|
|
|
|
/*
|
|
* If remaining data exceeds the mtu,
|
|
* we know we need more fragment(s).
|
|
*/
|
|
datalen = length + fraggap;
|
|
if (datalen > mtu - fragheaderlen)
|
|
datalen = maxfraglen - fragheaderlen;
|
|
fraglen = datalen + fragheaderlen;
|
|
pagedlen = 0;
|
|
|
|
alloc_extra = hh_len + 15;
|
|
alloc_extra += exthdrlen;
|
|
|
|
/* The last fragment gets additional space at tail.
|
|
* Note, with MSG_MORE we overallocate on fragments,
|
|
* because we have no idea what fragment will be
|
|
* the last.
|
|
*/
|
|
if (datalen == length + fraggap)
|
|
alloc_extra += rt->dst.trailer_len;
|
|
|
|
if ((flags & MSG_MORE) &&
|
|
!(rt->dst.dev->features&NETIF_F_SG))
|
|
alloclen = mtu;
|
|
else if (!paged &&
|
|
(fraglen + alloc_extra < SKB_MAX_ALLOC ||
|
|
!(rt->dst.dev->features & NETIF_F_SG)))
|
|
alloclen = fraglen;
|
|
else {
|
|
alloclen = fragheaderlen + transhdrlen;
|
|
pagedlen = datalen - transhdrlen;
|
|
}
|
|
|
|
alloclen += alloc_extra;
|
|
|
|
if (transhdrlen) {
|
|
skb = sock_alloc_send_skb(sk, alloclen,
|
|
(flags & MSG_DONTWAIT), &err);
|
|
} else {
|
|
skb = NULL;
|
|
if (refcount_read(&sk->sk_wmem_alloc) + wmem_alloc_delta <=
|
|
2 * sk->sk_sndbuf)
|
|
skb = alloc_skb(alloclen,
|
|
sk->sk_allocation);
|
|
if (unlikely(!skb))
|
|
err = -ENOBUFS;
|
|
}
|
|
if (!skb)
|
|
goto error;
|
|
|
|
/*
|
|
* Fill in the control structures
|
|
*/
|
|
skb->ip_summed = csummode;
|
|
skb->csum = 0;
|
|
skb_reserve(skb, hh_len);
|
|
|
|
/*
|
|
* Find where to start putting bytes.
|
|
*/
|
|
data = skb_put(skb, fraglen + exthdrlen - pagedlen);
|
|
skb_set_network_header(skb, exthdrlen);
|
|
skb->transport_header = (skb->network_header +
|
|
fragheaderlen);
|
|
data += fragheaderlen + exthdrlen;
|
|
|
|
if (fraggap) {
|
|
skb->csum = skb_copy_and_csum_bits(
|
|
skb_prev, maxfraglen,
|
|
data + transhdrlen, fraggap);
|
|
skb_prev->csum = csum_sub(skb_prev->csum,
|
|
skb->csum);
|
|
data += fraggap;
|
|
pskb_trim_unique(skb_prev, maxfraglen);
|
|
}
|
|
|
|
copy = datalen - transhdrlen - fraggap - pagedlen;
|
|
if (copy > 0 && getfrag(from, data + transhdrlen, offset, copy, fraggap, skb) < 0) {
|
|
err = -EFAULT;
|
|
kfree_skb(skb);
|
|
goto error;
|
|
}
|
|
|
|
offset += copy;
|
|
length -= copy + transhdrlen;
|
|
transhdrlen = 0;
|
|
exthdrlen = 0;
|
|
csummode = CHECKSUM_NONE;
|
|
|
|
/* only the initial fragment is time stamped */
|
|
skb_shinfo(skb)->tx_flags = cork->tx_flags;
|
|
cork->tx_flags = 0;
|
|
skb_shinfo(skb)->tskey = tskey;
|
|
tskey = 0;
|
|
skb_zcopy_set(skb, uarg, &extra_uref);
|
|
|
|
if ((flags & MSG_CONFIRM) && !skb_prev)
|
|
skb_set_dst_pending_confirm(skb, 1);
|
|
|
|
/*
|
|
* Put the packet on the pending queue.
|
|
*/
|
|
if (!skb->destructor) {
|
|
skb->destructor = sock_wfree;
|
|
skb->sk = sk;
|
|
wmem_alloc_delta += skb->truesize;
|
|
}
|
|
__skb_queue_tail(queue, skb);
|
|
continue;
|
|
}
|
|
|
|
if (copy > length)
|
|
copy = length;
|
|
|
|
if (!(rt->dst.dev->features&NETIF_F_SG) &&
|
|
skb_tailroom(skb) >= copy) {
|
|
unsigned int off;
|
|
|
|
off = skb->len;
|
|
if (getfrag(from, skb_put(skb, copy),
|
|
offset, copy, off, skb) < 0) {
|
|
__skb_trim(skb, off);
|
|
err = -EFAULT;
|
|
goto error;
|
|
}
|
|
} else if (!zc) {
|
|
int i = skb_shinfo(skb)->nr_frags;
|
|
|
|
err = -ENOMEM;
|
|
if (!sk_page_frag_refill(sk, pfrag))
|
|
goto error;
|
|
|
|
skb_zcopy_downgrade_managed(skb);
|
|
if (!skb_can_coalesce(skb, i, pfrag->page,
|
|
pfrag->offset)) {
|
|
err = -EMSGSIZE;
|
|
if (i == MAX_SKB_FRAGS)
|
|
goto error;
|
|
|
|
__skb_fill_page_desc(skb, i, pfrag->page,
|
|
pfrag->offset, 0);
|
|
skb_shinfo(skb)->nr_frags = ++i;
|
|
get_page(pfrag->page);
|
|
}
|
|
copy = min_t(int, copy, pfrag->size - pfrag->offset);
|
|
if (getfrag(from,
|
|
page_address(pfrag->page) + pfrag->offset,
|
|
offset, copy, skb->len, skb) < 0)
|
|
goto error_efault;
|
|
|
|
pfrag->offset += copy;
|
|
skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
|
|
skb_len_add(skb, copy);
|
|
wmem_alloc_delta += copy;
|
|
} else {
|
|
err = skb_zerocopy_iter_dgram(skb, from, copy);
|
|
if (err < 0)
|
|
goto error;
|
|
}
|
|
offset += copy;
|
|
length -= copy;
|
|
}
|
|
|
|
if (wmem_alloc_delta)
|
|
refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
|
|
return 0;
|
|
|
|
error_efault:
|
|
err = -EFAULT;
|
|
error:
|
|
net_zcopy_put_abort(uarg, extra_uref);
|
|
cork->length -= length;
|
|
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
|
|
refcount_add(wmem_alloc_delta, &sk->sk_wmem_alloc);
|
|
return err;
|
|
}
|
|
|
|
static int ip_setup_cork(struct sock *sk, struct inet_cork *cork,
|
|
struct ipcm_cookie *ipc, struct rtable **rtp)
|
|
{
|
|
struct ip_options_rcu *opt;
|
|
struct rtable *rt;
|
|
|
|
rt = *rtp;
|
|
if (unlikely(!rt))
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* setup for corking.
|
|
*/
|
|
opt = ipc->opt;
|
|
if (opt) {
|
|
if (!cork->opt) {
|
|
cork->opt = kmalloc(sizeof(struct ip_options) + 40,
|
|
sk->sk_allocation);
|
|
if (unlikely(!cork->opt))
|
|
return -ENOBUFS;
|
|
}
|
|
memcpy(cork->opt, &opt->opt, sizeof(struct ip_options) + opt->opt.optlen);
|
|
cork->flags |= IPCORK_OPT;
|
|
cork->addr = ipc->addr;
|
|
}
|
|
|
|
cork->fragsize = ip_sk_use_pmtu(sk) ?
|
|
dst_mtu(&rt->dst) : READ_ONCE(rt->dst.dev->mtu);
|
|
|
|
if (!inetdev_valid_mtu(cork->fragsize))
|
|
return -ENETUNREACH;
|
|
|
|
cork->gso_size = ipc->gso_size;
|
|
|
|
cork->dst = &rt->dst;
|
|
/* We stole this route, caller should not release it. */
|
|
*rtp = NULL;
|
|
|
|
cork->length = 0;
|
|
cork->ttl = ipc->ttl;
|
|
cork->tos = ipc->tos;
|
|
cork->mark = ipc->sockc.mark;
|
|
cork->priority = ipc->priority;
|
|
cork->transmit_time = ipc->sockc.transmit_time;
|
|
cork->tx_flags = 0;
|
|
sock_tx_timestamp(sk, ipc->sockc.tsflags, &cork->tx_flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* ip_append_data() and ip_append_page() can make one large IP datagram
|
|
* from many pieces of data. Each pieces will be holded on the socket
|
|
* until ip_push_pending_frames() is called. Each piece can be a page
|
|
* or non-page data.
|
|
*
|
|
* Not only UDP, other transport protocols - e.g. raw sockets - can use
|
|
* this interface potentially.
|
|
*
|
|
* LATER: length must be adjusted by pad at tail, when it is required.
|
|
*/
|
|
int ip_append_data(struct sock *sk, struct flowi4 *fl4,
|
|
int getfrag(void *from, char *to, int offset, int len,
|
|
int odd, struct sk_buff *skb),
|
|
void *from, int length, int transhdrlen,
|
|
struct ipcm_cookie *ipc, struct rtable **rtp,
|
|
unsigned int flags)
|
|
{
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
int err;
|
|
|
|
if (flags&MSG_PROBE)
|
|
return 0;
|
|
|
|
if (skb_queue_empty(&sk->sk_write_queue)) {
|
|
err = ip_setup_cork(sk, &inet->cork.base, ipc, rtp);
|
|
if (err)
|
|
return err;
|
|
} else {
|
|
transhdrlen = 0;
|
|
}
|
|
|
|
return __ip_append_data(sk, fl4, &sk->sk_write_queue, &inet->cork.base,
|
|
sk_page_frag(sk), getfrag,
|
|
from, length, transhdrlen, flags);
|
|
}
|
|
|
|
ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page,
|
|
int offset, size_t size, int flags)
|
|
{
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
struct sk_buff *skb;
|
|
struct rtable *rt;
|
|
struct ip_options *opt = NULL;
|
|
struct inet_cork *cork;
|
|
int hh_len;
|
|
int mtu;
|
|
int len;
|
|
int err;
|
|
unsigned int maxfraglen, fragheaderlen, fraggap, maxnonfragsize;
|
|
|
|
if (inet->hdrincl)
|
|
return -EPERM;
|
|
|
|
if (flags&MSG_PROBE)
|
|
return 0;
|
|
|
|
if (skb_queue_empty(&sk->sk_write_queue))
|
|
return -EINVAL;
|
|
|
|
cork = &inet->cork.base;
|
|
rt = (struct rtable *)cork->dst;
|
|
if (cork->flags & IPCORK_OPT)
|
|
opt = cork->opt;
|
|
|
|
if (!(rt->dst.dev->features & NETIF_F_SG))
|
|
return -EOPNOTSUPP;
|
|
|
|
hh_len = LL_RESERVED_SPACE(rt->dst.dev);
|
|
mtu = cork->gso_size ? IP_MAX_MTU : cork->fragsize;
|
|
|
|
fragheaderlen = sizeof(struct iphdr) + (opt ? opt->optlen : 0);
|
|
maxfraglen = ((mtu - fragheaderlen) & ~7) + fragheaderlen;
|
|
maxnonfragsize = ip_sk_ignore_df(sk) ? 0xFFFF : mtu;
|
|
|
|
if (cork->length + size > maxnonfragsize - fragheaderlen) {
|
|
ip_local_error(sk, EMSGSIZE, fl4->daddr, inet->inet_dport,
|
|
mtu - (opt ? opt->optlen : 0));
|
|
return -EMSGSIZE;
|
|
}
|
|
|
|
skb = skb_peek_tail(&sk->sk_write_queue);
|
|
if (!skb)
|
|
return -EINVAL;
|
|
|
|
cork->length += size;
|
|
|
|
while (size > 0) {
|
|
/* Check if the remaining data fits into current packet. */
|
|
len = mtu - skb->len;
|
|
if (len < size)
|
|
len = maxfraglen - skb->len;
|
|
|
|
if (len <= 0) {
|
|
struct sk_buff *skb_prev;
|
|
int alloclen;
|
|
|
|
skb_prev = skb;
|
|
fraggap = skb_prev->len - maxfraglen;
|
|
|
|
alloclen = fragheaderlen + hh_len + fraggap + 15;
|
|
skb = sock_wmalloc(sk, alloclen, 1, sk->sk_allocation);
|
|
if (unlikely(!skb)) {
|
|
err = -ENOBUFS;
|
|
goto error;
|
|
}
|
|
|
|
/*
|
|
* Fill in the control structures
|
|
*/
|
|
skb->ip_summed = CHECKSUM_NONE;
|
|
skb->csum = 0;
|
|
skb_reserve(skb, hh_len);
|
|
|
|
/*
|
|
* Find where to start putting bytes.
|
|
*/
|
|
skb_put(skb, fragheaderlen + fraggap);
|
|
skb_reset_network_header(skb);
|
|
skb->transport_header = (skb->network_header +
|
|
fragheaderlen);
|
|
if (fraggap) {
|
|
skb->csum = skb_copy_and_csum_bits(skb_prev,
|
|
maxfraglen,
|
|
skb_transport_header(skb),
|
|
fraggap);
|
|
skb_prev->csum = csum_sub(skb_prev->csum,
|
|
skb->csum);
|
|
pskb_trim_unique(skb_prev, maxfraglen);
|
|
}
|
|
|
|
/*
|
|
* Put the packet on the pending queue.
|
|
*/
|
|
__skb_queue_tail(&sk->sk_write_queue, skb);
|
|
continue;
|
|
}
|
|
|
|
if (len > size)
|
|
len = size;
|
|
|
|
if (skb_append_pagefrags(skb, page, offset, len)) {
|
|
err = -EMSGSIZE;
|
|
goto error;
|
|
}
|
|
|
|
if (skb->ip_summed == CHECKSUM_NONE) {
|
|
__wsum csum;
|
|
csum = csum_page(page, offset, len);
|
|
skb->csum = csum_block_add(skb->csum, csum, skb->len);
|
|
}
|
|
|
|
skb_len_add(skb, len);
|
|
refcount_add(len, &sk->sk_wmem_alloc);
|
|
offset += len;
|
|
size -= len;
|
|
}
|
|
return 0;
|
|
|
|
error:
|
|
cork->length -= size;
|
|
IP_INC_STATS(sock_net(sk), IPSTATS_MIB_OUTDISCARDS);
|
|
return err;
|
|
}
|
|
|
|
static void ip_cork_release(struct inet_cork *cork)
|
|
{
|
|
cork->flags &= ~IPCORK_OPT;
|
|
kfree(cork->opt);
|
|
cork->opt = NULL;
|
|
dst_release(cork->dst);
|
|
cork->dst = NULL;
|
|
}
|
|
|
|
/*
|
|
* Combined all pending IP fragments on the socket as one IP datagram
|
|
* and push them out.
|
|
*/
|
|
struct sk_buff *__ip_make_skb(struct sock *sk,
|
|
struct flowi4 *fl4,
|
|
struct sk_buff_head *queue,
|
|
struct inet_cork *cork)
|
|
{
|
|
struct sk_buff *skb, *tmp_skb;
|
|
struct sk_buff **tail_skb;
|
|
struct inet_sock *inet = inet_sk(sk);
|
|
struct net *net = sock_net(sk);
|
|
struct ip_options *opt = NULL;
|
|
struct rtable *rt = (struct rtable *)cork->dst;
|
|
struct iphdr *iph;
|
|
__be16 df = 0;
|
|
__u8 ttl;
|
|
|
|
skb = __skb_dequeue(queue);
|
|
if (!skb)
|
|
goto out;
|
|
tail_skb = &(skb_shinfo(skb)->frag_list);
|
|
|
|
/* move skb->data to ip header from ext header */
|
|
if (skb->data < skb_network_header(skb))
|
|
__skb_pull(skb, skb_network_offset(skb));
|
|
while ((tmp_skb = __skb_dequeue(queue)) != NULL) {
|
|
__skb_pull(tmp_skb, skb_network_header_len(skb));
|
|
*tail_skb = tmp_skb;
|
|
tail_skb = &(tmp_skb->next);
|
|
skb->len += tmp_skb->len;
|
|
skb->data_len += tmp_skb->len;
|
|
skb->truesize += tmp_skb->truesize;
|
|
tmp_skb->destructor = NULL;
|
|
tmp_skb->sk = NULL;
|
|
}
|
|
|
|
/* Unless user demanded real pmtu discovery (IP_PMTUDISC_DO), we allow
|
|
* to fragment the frame generated here. No matter, what transforms
|
|
* how transforms change size of the packet, it will come out.
|
|
*/
|
|
skb->ignore_df = ip_sk_ignore_df(sk);
|
|
|
|
/* DF bit is set when we want to see DF on outgoing frames.
|
|
* If ignore_df is set too, we still allow to fragment this frame
|
|
* locally. */
|
|
if (inet->pmtudisc == IP_PMTUDISC_DO ||
|
|
inet->pmtudisc == IP_PMTUDISC_PROBE ||
|
|
(skb->len <= dst_mtu(&rt->dst) &&
|
|
ip_dont_fragment(sk, &rt->dst)))
|
|
df = htons(IP_DF);
|
|
|
|
if (cork->flags & IPCORK_OPT)
|
|
opt = cork->opt;
|
|
|
|
if (cork->ttl != 0)
|
|
ttl = cork->ttl;
|
|
else if (rt->rt_type == RTN_MULTICAST)
|
|
ttl = inet->mc_ttl;
|
|
else
|
|
ttl = ip_select_ttl(inet, &rt->dst);
|
|
|
|
iph = ip_hdr(skb);
|
|
iph->version = 4;
|
|
iph->ihl = 5;
|
|
iph->tos = (cork->tos != -1) ? cork->tos : inet->tos;
|
|
iph->frag_off = df;
|
|
iph->ttl = ttl;
|
|
iph->protocol = sk->sk_protocol;
|
|
ip_copy_addrs(iph, fl4);
|
|
ip_select_ident(net, skb, sk);
|
|
|
|
if (opt) {
|
|
iph->ihl += opt->optlen >> 2;
|
|
ip_options_build(skb, opt, cork->addr, rt);
|
|
}
|
|
|
|
skb->priority = (cork->tos != -1) ? cork->priority: sk->sk_priority;
|
|
skb->mark = cork->mark;
|
|
skb->tstamp = cork->transmit_time;
|
|
/*
|
|
* Steal rt from cork.dst to avoid a pair of atomic_inc/atomic_dec
|
|
* on dst refcount
|
|
*/
|
|
cork->dst = NULL;
|
|
skb_dst_set(skb, &rt->dst);
|
|
|
|
if (iph->protocol == IPPROTO_ICMP) {
|
|
u8 icmp_type;
|
|
|
|
/* For such sockets, transhdrlen is zero when do ip_append_data(),
|
|
* so icmphdr does not in skb linear region and can not get icmp_type
|
|
* by icmp_hdr(skb)->type.
|
|
*/
|
|
if (sk->sk_type == SOCK_RAW && !inet_sk(sk)->hdrincl)
|
|
icmp_type = fl4->fl4_icmp_type;
|
|
else
|
|
icmp_type = icmp_hdr(skb)->type;
|
|
icmp_out_count(net, icmp_type);
|
|
}
|
|
|
|
ip_cork_release(cork);
|
|
out:
|
|
return skb;
|
|
}
|
|
|
|
int ip_send_skb(struct net *net, struct sk_buff *skb)
|
|
{
|
|
int err;
|
|
|
|
err = ip_local_out(net, skb->sk, skb);
|
|
if (err) {
|
|
if (err > 0)
|
|
err = net_xmit_errno(err);
|
|
if (err)
|
|
IP_INC_STATS(net, IPSTATS_MIB_OUTDISCARDS);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
int ip_push_pending_frames(struct sock *sk, struct flowi4 *fl4)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
skb = ip_finish_skb(sk, fl4);
|
|
if (!skb)
|
|
return 0;
|
|
|
|
/* Netfilter gets whole the not fragmented skb. */
|
|
return ip_send_skb(sock_net(sk), skb);
|
|
}
|
|
|
|
/*
|
|
* Throw away all pending data on the socket.
|
|
*/
|
|
static void __ip_flush_pending_frames(struct sock *sk,
|
|
struct sk_buff_head *queue,
|
|
struct inet_cork *cork)
|
|
{
|
|
struct sk_buff *skb;
|
|
|
|
while ((skb = __skb_dequeue_tail(queue)) != NULL)
|
|
kfree_skb(skb);
|
|
|
|
ip_cork_release(cork);
|
|
}
|
|
|
|
void ip_flush_pending_frames(struct sock *sk)
|
|
{
|
|
__ip_flush_pending_frames(sk, &sk->sk_write_queue, &inet_sk(sk)->cork.base);
|
|
}
|
|
|
|
struct sk_buff *ip_make_skb(struct sock *sk,
|
|
struct flowi4 *fl4,
|
|
int getfrag(void *from, char *to, int offset,
|
|
int len, int odd, struct sk_buff *skb),
|
|
void *from, int length, int transhdrlen,
|
|
struct ipcm_cookie *ipc, struct rtable **rtp,
|
|
struct inet_cork *cork, unsigned int flags)
|
|
{
|
|
struct sk_buff_head queue;
|
|
int err;
|
|
|
|
if (flags & MSG_PROBE)
|
|
return NULL;
|
|
|
|
__skb_queue_head_init(&queue);
|
|
|
|
cork->flags = 0;
|
|
cork->addr = 0;
|
|
cork->opt = NULL;
|
|
err = ip_setup_cork(sk, cork, ipc, rtp);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
|
|
err = __ip_append_data(sk, fl4, &queue, cork,
|
|
¤t->task_frag, getfrag,
|
|
from, length, transhdrlen, flags);
|
|
if (err) {
|
|
__ip_flush_pending_frames(sk, &queue, cork);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
return __ip_make_skb(sk, fl4, &queue, cork);
|
|
}
|
|
|
|
/*
|
|
* Fetch data from kernel space and fill in checksum if needed.
|
|
*/
|
|
static int ip_reply_glue_bits(void *dptr, char *to, int offset,
|
|
int len, int odd, struct sk_buff *skb)
|
|
{
|
|
__wsum csum;
|
|
|
|
csum = csum_partial_copy_nocheck(dptr+offset, to, len);
|
|
skb->csum = csum_block_add(skb->csum, csum, odd);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Generic function to send a packet as reply to another packet.
|
|
* Used to send some TCP resets/acks so far.
|
|
*/
|
|
void ip_send_unicast_reply(struct sock *sk, struct sk_buff *skb,
|
|
const struct ip_options *sopt,
|
|
__be32 daddr, __be32 saddr,
|
|
const struct ip_reply_arg *arg,
|
|
unsigned int len, u64 transmit_time)
|
|
{
|
|
struct ip_options_data replyopts;
|
|
struct ipcm_cookie ipc;
|
|
struct flowi4 fl4;
|
|
struct rtable *rt = skb_rtable(skb);
|
|
struct net *net = sock_net(sk);
|
|
struct sk_buff *nskb;
|
|
int err;
|
|
int oif;
|
|
|
|
if (__ip_options_echo(net, &replyopts.opt.opt, skb, sopt))
|
|
return;
|
|
|
|
ipcm_init(&ipc);
|
|
ipc.addr = daddr;
|
|
ipc.sockc.transmit_time = transmit_time;
|
|
|
|
if (replyopts.opt.opt.optlen) {
|
|
ipc.opt = &replyopts.opt;
|
|
|
|
if (replyopts.opt.opt.srr)
|
|
daddr = replyopts.opt.opt.faddr;
|
|
}
|
|
|
|
oif = arg->bound_dev_if;
|
|
if (!oif && netif_index_is_l3_master(net, skb->skb_iif))
|
|
oif = skb->skb_iif;
|
|
|
|
flowi4_init_output(&fl4, oif,
|
|
IP4_REPLY_MARK(net, skb->mark) ?: sk->sk_mark,
|
|
RT_TOS(arg->tos),
|
|
RT_SCOPE_UNIVERSE, ip_hdr(skb)->protocol,
|
|
ip_reply_arg_flowi_flags(arg),
|
|
daddr, saddr,
|
|
tcp_hdr(skb)->source, tcp_hdr(skb)->dest,
|
|
arg->uid);
|
|
security_skb_classify_flow(skb, flowi4_to_flowi_common(&fl4));
|
|
rt = ip_route_output_flow(net, &fl4, sk);
|
|
if (IS_ERR(rt))
|
|
return;
|
|
|
|
inet_sk(sk)->tos = arg->tos & ~INET_ECN_MASK;
|
|
|
|
sk->sk_protocol = ip_hdr(skb)->protocol;
|
|
sk->sk_bound_dev_if = arg->bound_dev_if;
|
|
sk->sk_sndbuf = READ_ONCE(sysctl_wmem_default);
|
|
ipc.sockc.mark = fl4.flowi4_mark;
|
|
err = ip_append_data(sk, &fl4, ip_reply_glue_bits, arg->iov->iov_base,
|
|
len, 0, &ipc, &rt, MSG_DONTWAIT);
|
|
if (unlikely(err)) {
|
|
ip_flush_pending_frames(sk);
|
|
goto out;
|
|
}
|
|
|
|
nskb = skb_peek(&sk->sk_write_queue);
|
|
if (nskb) {
|
|
if (arg->csumoffset >= 0)
|
|
*((__sum16 *)skb_transport_header(nskb) +
|
|
arg->csumoffset) = csum_fold(csum_add(nskb->csum,
|
|
arg->csum));
|
|
nskb->ip_summed = CHECKSUM_NONE;
|
|
nskb->mono_delivery_time = !!transmit_time;
|
|
ip_push_pending_frames(sk, &fl4);
|
|
}
|
|
out:
|
|
ip_rt_put(rt);
|
|
}
|
|
|
|
void __init ip_init(void)
|
|
{
|
|
ip_rt_init();
|
|
inet_initpeers();
|
|
|
|
#if defined(CONFIG_IP_MULTICAST)
|
|
igmp_mc_init();
|
|
#endif
|
|
}
|