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OpenCloudOS-Kernel/net/xfrm/xfrm_output.c

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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* xfrm_output.c - Common IPsec encapsulation code.
*
* Copyright (c) 2007 Herbert Xu <herbert@gondor.apana.org.au>
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/netfilter.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <net/dst.h>
#include <net/gso.h>
#include <net/icmp.h>
#include <net/inet_ecn.h>
#include <net/xfrm.h>
#if IS_ENABLED(CONFIG_IPV6)
#include <net/ip6_route.h>
#include <net/ipv6_stubs.h>
#endif
#include "xfrm_inout.h"
static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb);
static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb);
static int xfrm_skb_check_space(struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
int nhead = dst->header_len + LL_RESERVED_SPACE(dst->dev)
- skb_headroom(skb);
int ntail = dst->dev->needed_tailroom - skb_tailroom(skb);
if (nhead <= 0) {
if (ntail <= 0)
return 0;
nhead = 0;
} else if (ntail < 0)
ntail = 0;
return pskb_expand_head(skb, nhead, ntail, GFP_ATOMIC);
}
/* Children define the path of the packet through the
* Linux networking. Thus, destinations are stackable.
*/
static struct dst_entry *skb_dst_pop(struct sk_buff *skb)
{
struct dst_entry *child = dst_clone(xfrm_dst_child(skb_dst(skb)));
skb_dst_drop(skb);
return child;
}
/* Add encapsulation header.
*
* The IP header will be moved forward to make space for the encapsulation
* header.
*/
static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
{
struct iphdr *iph = ip_hdr(skb);
int ihl = iph->ihl * 4;
skb_set_inner_transport_header(skb, skb_transport_offset(skb));
skb_set_network_header(skb, -x->props.header_len);
skb->mac_header = skb->network_header +
offsetof(struct iphdr, protocol);
skb->transport_header = skb->network_header + ihl;
__skb_pull(skb, ihl);
memmove(skb_network_header(skb), iph, ihl);
return 0;
}
#if IS_ENABLED(CONFIG_IPV6_MIP6)
static int mip6_rthdr_offset(struct sk_buff *skb, u8 **nexthdr, int type)
{
const unsigned char *nh = skb_network_header(skb);
unsigned int offset = sizeof(struct ipv6hdr);
unsigned int packet_len;
int found_rhdr = 0;
packet_len = skb_tail_pointer(skb) - nh;
*nexthdr = &ipv6_hdr(skb)->nexthdr;
while (offset <= packet_len) {
struct ipv6_opt_hdr *exthdr;
switch (**nexthdr) {
case NEXTHDR_HOP:
break;
case NEXTHDR_ROUTING:
if (type == IPPROTO_ROUTING && offset + 3 <= packet_len) {
struct ipv6_rt_hdr *rt;
rt = (struct ipv6_rt_hdr *)(nh + offset);
if (rt->type != 0)
return offset;
}
found_rhdr = 1;
break;
case NEXTHDR_DEST:
/* HAO MUST NOT appear more than once.
* XXX: It is better to try to find by the end of
* XXX: packet if HAO exists.
*/
if (ipv6_find_tlv(skb, offset, IPV6_TLV_HAO) >= 0) {
net_dbg_ratelimited("mip6: hao exists already, override\n");
return offset;
}
if (found_rhdr)
return offset;
break;
default:
return offset;
}
if (offset + sizeof(struct ipv6_opt_hdr) > packet_len)
return -EINVAL;
exthdr = (struct ipv6_opt_hdr *)(skb_network_header(skb) +
offset);
offset += ipv6_optlen(exthdr);
if (offset > IPV6_MAXPLEN)
return -EINVAL;
*nexthdr = &exthdr->nexthdr;
}
return -EINVAL;
}
#endif
#if IS_ENABLED(CONFIG_IPV6)
static int xfrm6_hdr_offset(struct xfrm_state *x, struct sk_buff *skb, u8 **prevhdr)
{
switch (x->type->proto) {
#if IS_ENABLED(CONFIG_IPV6_MIP6)
case IPPROTO_DSTOPTS:
case IPPROTO_ROUTING:
return mip6_rthdr_offset(skb, prevhdr, x->type->proto);
#endif
default:
break;
}
return ip6_find_1stfragopt(skb, prevhdr);
}
#endif
/* Add encapsulation header.
*
* The IP header and mutable extension headers will be moved forward to make
* space for the encapsulation header.
*/
static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_IPV6)
struct ipv6hdr *iph;
u8 *prevhdr;
int hdr_len;
iph = ipv6_hdr(skb);
skb_set_inner_transport_header(skb, skb_transport_offset(skb));
hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
if (hdr_len < 0)
return hdr_len;
skb_set_mac_header(skb,
(prevhdr - x->props.header_len) - skb->data);
skb_set_network_header(skb, -x->props.header_len);
skb->transport_header = skb->network_header + hdr_len;
__skb_pull(skb, hdr_len);
memmove(ipv6_hdr(skb), iph, hdr_len);
return 0;
#else
WARN_ON_ONCE(1);
return -EAFNOSUPPORT;
#endif
}
/* Add route optimization header space.
*
* The IP header and mutable extension headers will be moved forward to make
* space for the route optimization header.
*/
static int xfrm6_ro_output(struct xfrm_state *x, struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_IPV6)
struct ipv6hdr *iph;
u8 *prevhdr;
int hdr_len;
iph = ipv6_hdr(skb);
hdr_len = xfrm6_hdr_offset(x, skb, &prevhdr);
if (hdr_len < 0)
return hdr_len;
skb_set_mac_header(skb,
(prevhdr - x->props.header_len) - skb->data);
skb_set_network_header(skb, -x->props.header_len);
skb->transport_header = skb->network_header + hdr_len;
__skb_pull(skb, hdr_len);
memmove(ipv6_hdr(skb), iph, hdr_len);
return 0;
#else
WARN_ON_ONCE(1);
return -EAFNOSUPPORT;
#endif
}
/* Add encapsulation header.
*
* The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
*/
static int xfrm4_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
{
struct ip_beet_phdr *ph;
struct iphdr *top_iph;
int hdrlen, optlen;
hdrlen = 0;
optlen = XFRM_MODE_SKB_CB(skb)->optlen;
if (unlikely(optlen))
hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
skb_set_network_header(skb, -x->props.header_len - hdrlen +
(XFRM_MODE_SKB_CB(skb)->ihl - sizeof(*top_iph)));
if (x->sel.family != AF_INET6)
skb->network_header += IPV4_BEET_PHMAXLEN;
skb->mac_header = skb->network_header +
offsetof(struct iphdr, protocol);
skb->transport_header = skb->network_header + sizeof(*top_iph);
xfrm4_beet_make_header(skb);
ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
top_iph = ip_hdr(skb);
if (unlikely(optlen)) {
if (WARN_ON(optlen < 0))
return -EINVAL;
ph->padlen = 4 - (optlen & 4);
ph->hdrlen = optlen / 8;
ph->nexthdr = top_iph->protocol;
if (ph->padlen)
memset(ph + 1, IPOPT_NOP, ph->padlen);
top_iph->protocol = IPPROTO_BEETPH;
top_iph->ihl = sizeof(struct iphdr) / 4;
}
top_iph->saddr = x->props.saddr.a4;
top_iph->daddr = x->id.daddr.a4;
return 0;
}
/* Add encapsulation header.
*
* The top IP header will be constructed per RFC 2401.
*/
static int xfrm4_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
{
bool small_ipv6 = (skb->protocol == htons(ETH_P_IPV6)) && (skb->len <= IPV6_MIN_MTU);
struct dst_entry *dst = skb_dst(skb);
struct iphdr *top_iph;
int flags;
skb_set_inner_network_header(skb, skb_network_offset(skb));
skb_set_inner_transport_header(skb, skb_transport_offset(skb));
skb_set_network_header(skb, -x->props.header_len);
skb->mac_header = skb->network_header +
offsetof(struct iphdr, protocol);
skb->transport_header = skb->network_header + sizeof(*top_iph);
top_iph = ip_hdr(skb);
top_iph->ihl = 5;
top_iph->version = 4;
top_iph->protocol = xfrm_af2proto(skb_dst(skb)->ops->family);
/* DS disclosing depends on XFRM_SA_XFLAG_DONT_ENCAP_DSCP */
if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
top_iph->tos = 0;
else
top_iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
top_iph->tos = INET_ECN_encapsulate(top_iph->tos,
XFRM_MODE_SKB_CB(skb)->tos);
flags = x->props.flags;
if (flags & XFRM_STATE_NOECN)
IP_ECN_clear(top_iph);
top_iph->frag_off = (flags & XFRM_STATE_NOPMTUDISC) || small_ipv6 ?
0 : (XFRM_MODE_SKB_CB(skb)->frag_off & htons(IP_DF));
top_iph->ttl = ip4_dst_hoplimit(xfrm_dst_child(dst));
top_iph->saddr = x->props.saddr.a4;
top_iph->daddr = x->id.daddr.a4;
ip_select_ident(dev_net(dst->dev), skb, NULL);
return 0;
}
#if IS_ENABLED(CONFIG_IPV6)
static int xfrm6_tunnel_encap_add(struct xfrm_state *x, struct sk_buff *skb)
{
struct dst_entry *dst = skb_dst(skb);
struct ipv6hdr *top_iph;
int dsfield;
skb_set_inner_network_header(skb, skb_network_offset(skb));
skb_set_inner_transport_header(skb, skb_transport_offset(skb));
skb_set_network_header(skb, -x->props.header_len);
skb->mac_header = skb->network_header +
offsetof(struct ipv6hdr, nexthdr);
skb->transport_header = skb->network_header + sizeof(*top_iph);
top_iph = ipv6_hdr(skb);
top_iph->version = 6;
memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
sizeof(top_iph->flow_lbl));
top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
dsfield = 0;
else
dsfield = XFRM_MODE_SKB_CB(skb)->tos;
dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
if (x->props.flags & XFRM_STATE_NOECN)
dsfield &= ~INET_ECN_MASK;
ipv6_change_dsfield(top_iph, 0, dsfield);
top_iph->hop_limit = ip6_dst_hoplimit(xfrm_dst_child(dst));
top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
return 0;
}
static int xfrm6_beet_encap_add(struct xfrm_state *x, struct sk_buff *skb)
{
struct ipv6hdr *top_iph;
struct ip_beet_phdr *ph;
int optlen, hdr_len;
hdr_len = 0;
optlen = XFRM_MODE_SKB_CB(skb)->optlen;
if (unlikely(optlen))
hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
skb_set_network_header(skb, -x->props.header_len - hdr_len);
if (x->sel.family != AF_INET6)
skb->network_header += IPV4_BEET_PHMAXLEN;
skb->mac_header = skb->network_header +
offsetof(struct ipv6hdr, nexthdr);
skb->transport_header = skb->network_header + sizeof(*top_iph);
ph = __skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdr_len);
xfrm6_beet_make_header(skb);
top_iph = ipv6_hdr(skb);
if (unlikely(optlen)) {
if (WARN_ON(optlen < 0))
return -EINVAL;
ph->padlen = 4 - (optlen & 4);
ph->hdrlen = optlen / 8;
ph->nexthdr = top_iph->nexthdr;
if (ph->padlen)
memset(ph + 1, IPOPT_NOP, ph->padlen);
top_iph->nexthdr = IPPROTO_BEETPH;
}
top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
return 0;
}
#endif
/* Add encapsulation header.
*
* On exit, the transport header will be set to the start of the
* encapsulation header to be filled in by x->type->output and the mac
* header will be set to the nextheader (protocol for IPv4) field of the
* extension header directly preceding the encapsulation header, or in
* its absence, that of the top IP header.
* The value of the network header will always point to the top IP header
* while skb->data will point to the payload.
*/
static int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
err = xfrm_inner_extract_output(x, skb);
if (err)
return err;
IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
skb->protocol = htons(ETH_P_IP);
switch (x->props.mode) {
case XFRM_MODE_BEET:
return xfrm4_beet_encap_add(x, skb);
case XFRM_MODE_TUNNEL:
return xfrm4_tunnel_encap_add(x, skb);
}
WARN_ON_ONCE(1);
return -EOPNOTSUPP;
}
static int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_IPV6)
int err;
err = xfrm_inner_extract_output(x, skb);
if (err)
return err;
skb->ignore_df = 1;
skb->protocol = htons(ETH_P_IPV6);
switch (x->props.mode) {
case XFRM_MODE_BEET:
return xfrm6_beet_encap_add(x, skb);
case XFRM_MODE_TUNNEL:
return xfrm6_tunnel_encap_add(x, skb);
default:
WARN_ON_ONCE(1);
return -EOPNOTSUPP;
}
#endif
WARN_ON_ONCE(1);
return -EAFNOSUPPORT;
}
static int xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
{
switch (x->props.mode) {
case XFRM_MODE_BEET:
case XFRM_MODE_TUNNEL:
if (x->props.family == AF_INET)
return xfrm4_prepare_output(x, skb);
if (x->props.family == AF_INET6)
return xfrm6_prepare_output(x, skb);
break;
case XFRM_MODE_TRANSPORT:
if (x->props.family == AF_INET)
return xfrm4_transport_output(x, skb);
if (x->props.family == AF_INET6)
return xfrm6_transport_output(x, skb);
break;
case XFRM_MODE_ROUTEOPTIMIZATION:
if (x->props.family == AF_INET6)
return xfrm6_ro_output(x, skb);
WARN_ON_ONCE(1);
break;
default:
WARN_ON_ONCE(1);
break;
}
return -EOPNOTSUPP;
}
#if IS_ENABLED(CONFIG_NET_PKTGEN)
int pktgen_xfrm_outer_mode_output(struct xfrm_state *x, struct sk_buff *skb)
{
return xfrm_outer_mode_output(x, skb);
}
EXPORT_SYMBOL_GPL(pktgen_xfrm_outer_mode_output);
#endif
static int xfrm_output_one(struct sk_buff *skb, int err)
{
struct dst_entry *dst = skb_dst(skb);
struct xfrm_state *x = dst->xfrm;
struct net *net = xs_net(x);
if (err <= 0 || x->xso.type == XFRM_DEV_OFFLOAD_PACKET)
goto resume;
do {
err = xfrm_skb_check_space(skb);
if (err) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
goto error_nolock;
}
skb->mark = xfrm_smark_get(skb->mark, x);
err = xfrm_outer_mode_output(x, skb);
if (err) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEMODEERROR);
goto error_nolock;
}
spin_lock_bh(&x->lock);
if (unlikely(x->km.state != XFRM_STATE_VALID)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEINVALID);
err = -EINVAL;
goto error;
}
err = xfrm_state_check_expire(x);
if (err) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEEXPIRED);
goto error;
}
err = xfrm_replay_overflow(x, skb);
if (err) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATESEQERROR);
goto error;
}
x->curlft.bytes += skb->len;
x->curlft.packets++;
x->lastused = ktime_get_real_seconds();
spin_unlock_bh(&x->lock);
skb_dst_force(skb);
if (!skb_dst(skb)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
err = -EHOSTUNREACH;
goto error_nolock;
}
if (xfrm_offload(skb)) {
x->type_offload->encap(x, skb);
} else {
/* Inner headers are invalid now. */
skb->encapsulation = 0;
err = x->type->output(x, skb);
if (err == -EINPROGRESS)
goto out;
}
resume:
if (err) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTSTATEPROTOERROR);
goto error_nolock;
}
dst = skb_dst_pop(skb);
if (!dst) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
err = -EHOSTUNREACH;
goto error_nolock;
}
skb_dst_set(skb, dst);
x = dst->xfrm;
} while (x && !(x->outer_mode.flags & XFRM_MODE_FLAG_TUNNEL));
return 0;
error:
spin_unlock_bh(&x->lock);
error_nolock:
kfree_skb(skb);
out:
return err;
}
int xfrm_output_resume(struct sock *sk, struct sk_buff *skb, int err)
{
struct net *net = xs_net(skb_dst(skb)->xfrm);
while (likely((err = xfrm_output_one(skb, err)) == 0)) {
nf_reset_ct(skb);
err = skb_dst(skb)->ops->local_out(net, sk, skb);
if (unlikely(err != 1))
goto out;
if (!skb_dst(skb)->xfrm)
return dst_output(net, sk, skb);
err = nf_hook(skb_dst(skb)->ops->family,
NF_INET_POST_ROUTING, net, sk, skb,
NULL, skb_dst(skb)->dev, xfrm_output2);
if (unlikely(err != 1))
goto out;
}
if (err == -EINPROGRESS)
err = 0;
out:
return err;
}
EXPORT_SYMBOL_GPL(xfrm_output_resume);
static int xfrm_output2(struct net *net, struct sock *sk, struct sk_buff *skb)
{
return xfrm_output_resume(sk, skb, 1);
}
static int xfrm_output_gso(struct net *net, struct sock *sk, struct sk_buff *skb)
{
struct sk_buff *segs, *nskb;
BUILD_BUG_ON(sizeof(*IPCB(skb)) > SKB_GSO_CB_OFFSET);
BUILD_BUG_ON(sizeof(*IP6CB(skb)) > SKB_GSO_CB_OFFSET);
segs = skb_gso_segment(skb, 0);
kfree_skb(skb);
if (IS_ERR(segs))
return PTR_ERR(segs);
if (segs == NULL)
return -EINVAL;
skb_list_walk_safe(segs, segs, nskb) {
int err;
skb_mark_not_on_list(segs);
err = xfrm_output2(net, sk, segs);
if (unlikely(err)) {
kfree_skb_list(nskb);
return err;
}
}
return 0;
}
/* For partial checksum offload, the outer header checksum is calculated
* by software and the inner header checksum is calculated by hardware.
* This requires hardware to know the inner packet type to calculate
* the inner header checksum. Save inner ip protocol here to avoid
* traversing the packet in the vendor's xmit code.
* For IPsec tunnel mode save the ip protocol from the IP header of the
* plain text packet. Otherwise If the encap type is IPIP, just save
* skb->inner_ipproto in any other case get the ip protocol from the IP
* header.
*/
static void xfrm_get_inner_ipproto(struct sk_buff *skb, struct xfrm_state *x)
{
struct xfrm_offload *xo = xfrm_offload(skb);
const struct ethhdr *eth;
if (!xo)
return;
if (x->outer_mode.encap == XFRM_MODE_TUNNEL) {
switch (x->outer_mode.family) {
case AF_INET:
xo->inner_ipproto = ip_hdr(skb)->protocol;
break;
case AF_INET6:
xo->inner_ipproto = ipv6_hdr(skb)->nexthdr;
break;
default:
break;
}
return;
}
/* non-Tunnel Mode */
if (!skb->encapsulation)
return;
if (skb->inner_protocol_type == ENCAP_TYPE_IPPROTO) {
xo->inner_ipproto = skb->inner_ipproto;
return;
}
if (skb->inner_protocol_type != ENCAP_TYPE_ETHER)
return;
eth = (struct ethhdr *)skb_inner_mac_header(skb);
switch (ntohs(eth->h_proto)) {
case ETH_P_IPV6:
xo->inner_ipproto = inner_ipv6_hdr(skb)->nexthdr;
break;
case ETH_P_IP:
xo->inner_ipproto = inner_ip_hdr(skb)->protocol;
break;
}
}
int xfrm_output(struct sock *sk, struct sk_buff *skb)
{
struct net *net = dev_net(skb_dst(skb)->dev);
struct xfrm_state *x = skb_dst(skb)->xfrm;
int family;
int err;
family = (x->xso.type != XFRM_DEV_OFFLOAD_PACKET) ? x->outer_mode.family
: skb_dst(skb)->ops->family;
switch (family) {
case AF_INET:
memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
break;
case AF_INET6:
memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
break;
}
if (x->xso.type == XFRM_DEV_OFFLOAD_PACKET) {
if (!xfrm_dev_offload_ok(skb, x)) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
kfree_skb(skb);
return -EHOSTUNREACH;
}
return xfrm_output_resume(sk, skb, 0);
}
secpath_reset(skb);
if (xfrm_dev_offload_ok(skb, x)) {
struct sec_path *sp;
sp = secpath_set(skb);
if (!sp) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
kfree_skb(skb);
return -ENOMEM;
}
sp->olen++;
sp->xvec[sp->len++] = x;
xfrm_state_hold(x);
xfrm_get_inner_ipproto(skb, x);
skb->encapsulation = 1;
if (skb_is_gso(skb)) {
if (skb->inner_protocol)
return xfrm_output_gso(net, sk, skb);
skb_shinfo(skb)->gso_type |= SKB_GSO_ESP;
goto out;
}
if (x->xso.dev && x->xso.dev->features & NETIF_F_HW_ESP_TX_CSUM)
goto out;
} else {
if (skb_is_gso(skb))
return xfrm_output_gso(net, sk, skb);
}
if (skb->ip_summed == CHECKSUM_PARTIAL) {
err = skb_checksum_help(skb);
if (err) {
XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTERROR);
kfree_skb(skb);
return err;
}
}
out:
return xfrm_output2(net, sk, skb);
}
EXPORT_SYMBOL_GPL(xfrm_output);
static int xfrm4_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
goto out;
if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
goto out;
mtu = dst_mtu(skb_dst(skb));
if ((!skb_is_gso(skb) && skb->len > mtu) ||
(skb_is_gso(skb) &&
!skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
skb->protocol = htons(ETH_P_IP);
if (skb->sk)
xfrm_local_error(skb, mtu);
else
icmp_send(skb, ICMP_DEST_UNREACH,
ICMP_FRAG_NEEDED, htonl(mtu));
ret = -EMSGSIZE;
}
out:
return ret;
}
static int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
int err;
if (x->outer_mode.encap == XFRM_MODE_BEET &&
ip_is_fragment(ip_hdr(skb))) {
net_warn_ratelimited("BEET mode doesn't support inner IPv4 fragments\n");
return -EAFNOSUPPORT;
}
err = xfrm4_tunnel_check_size(skb);
if (err)
return err;
XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
xfrm4_extract_header(skb);
return 0;
}
#if IS_ENABLED(CONFIG_IPV6)
static int xfrm6_tunnel_check_size(struct sk_buff *skb)
{
int mtu, ret = 0;
struct dst_entry *dst = skb_dst(skb);
if (skb->ignore_df)
goto out;
mtu = dst_mtu(dst);
if (mtu < IPV6_MIN_MTU)
mtu = IPV6_MIN_MTU;
if ((!skb_is_gso(skb) && skb->len > mtu) ||
(skb_is_gso(skb) &&
!skb_gso_validate_network_len(skb, ip6_skb_dst_mtu(skb)))) {
skb->dev = dst->dev;
skb->protocol = htons(ETH_P_IPV6);
if (xfrm6_local_dontfrag(skb->sk))
ipv6_stub->xfrm6_local_rxpmtu(skb, mtu);
else if (skb->sk)
xfrm_local_error(skb, mtu);
else
icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
ret = -EMSGSIZE;
}
out:
return ret;
}
#endif
static int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_IPV6)
int err;
err = xfrm6_tunnel_check_size(skb);
if (err)
return err;
XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
xfrm6_extract_header(skb);
return 0;
#else
WARN_ON_ONCE(1);
return -EAFNOSUPPORT;
#endif
}
static int xfrm_inner_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
switch (skb->protocol) {
case htons(ETH_P_IP):
return xfrm4_extract_output(x, skb);
case htons(ETH_P_IPV6):
return xfrm6_extract_output(x, skb);
}
return -EAFNOSUPPORT;
}
void xfrm_local_error(struct sk_buff *skb, int mtu)
{
unsigned int proto;
struct xfrm_state_afinfo *afinfo;
if (skb->protocol == htons(ETH_P_IP))
proto = AF_INET;
else if (skb->protocol == htons(ETH_P_IPV6) &&
skb->sk->sk_family == AF_INET6)
proto = AF_INET6;
else
return;
afinfo = xfrm_state_get_afinfo(proto);
if (afinfo) {
afinfo->local_error(skb, mtu);
rcu_read_unlock();
}
}
EXPORT_SYMBOL_GPL(xfrm_local_error);
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