389 lines
8.9 KiB
C
389 lines
8.9 KiB
C
#include <linux/skbuff.h>
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#include <linux/export.h>
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#include <linux/ip.h>
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#include <linux/ipv6.h>
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#include <linux/if_vlan.h>
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#include <net/ip.h>
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#include <net/ipv6.h>
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#include <linux/igmp.h>
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#include <linux/icmp.h>
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#include <linux/sctp.h>
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#include <linux/dccp.h>
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#include <linux/if_tunnel.h>
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#include <linux/if_pppox.h>
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#include <linux/ppp_defs.h>
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#include <net/flow_keys.h>
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/* copy saddr & daddr, possibly using 64bit load/store
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* Equivalent to : flow->src = iph->saddr;
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* flow->dst = iph->daddr;
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*/
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static void iph_to_flow_copy_addrs(struct flow_keys *flow, const struct iphdr *iph)
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{
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BUILD_BUG_ON(offsetof(typeof(*flow), dst) !=
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offsetof(typeof(*flow), src) + sizeof(flow->src));
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memcpy(&flow->src, &iph->saddr, sizeof(flow->src) + sizeof(flow->dst));
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}
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bool skb_flow_dissect(const struct sk_buff *skb, struct flow_keys *flow)
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{
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int poff, nhoff = skb_network_offset(skb);
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u8 ip_proto;
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__be16 proto = skb->protocol;
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memset(flow, 0, sizeof(*flow));
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again:
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switch (proto) {
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case __constant_htons(ETH_P_IP): {
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const struct iphdr *iph;
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struct iphdr _iph;
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ip:
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iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
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if (!iph)
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return false;
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if (ip_is_fragment(iph))
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ip_proto = 0;
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else
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ip_proto = iph->protocol;
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iph_to_flow_copy_addrs(flow, iph);
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nhoff += iph->ihl * 4;
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break;
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}
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case __constant_htons(ETH_P_IPV6): {
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const struct ipv6hdr *iph;
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struct ipv6hdr _iph;
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ipv6:
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iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
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if (!iph)
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return false;
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ip_proto = iph->nexthdr;
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flow->src = (__force __be32)ipv6_addr_hash(&iph->saddr);
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flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
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nhoff += sizeof(struct ipv6hdr);
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break;
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}
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case __constant_htons(ETH_P_8021AD):
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case __constant_htons(ETH_P_8021Q): {
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const struct vlan_hdr *vlan;
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struct vlan_hdr _vlan;
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vlan = skb_header_pointer(skb, nhoff, sizeof(_vlan), &_vlan);
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if (!vlan)
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return false;
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proto = vlan->h_vlan_encapsulated_proto;
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nhoff += sizeof(*vlan);
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goto again;
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}
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case __constant_htons(ETH_P_PPP_SES): {
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struct {
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struct pppoe_hdr hdr;
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__be16 proto;
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} *hdr, _hdr;
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hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
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if (!hdr)
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return false;
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proto = hdr->proto;
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nhoff += PPPOE_SES_HLEN;
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switch (proto) {
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case __constant_htons(PPP_IP):
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goto ip;
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case __constant_htons(PPP_IPV6):
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goto ipv6;
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default:
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return false;
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}
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}
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default:
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return false;
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}
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switch (ip_proto) {
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case IPPROTO_GRE: {
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struct gre_hdr {
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__be16 flags;
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__be16 proto;
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} *hdr, _hdr;
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hdr = skb_header_pointer(skb, nhoff, sizeof(_hdr), &_hdr);
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if (!hdr)
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return false;
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/*
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* Only look inside GRE if version zero and no
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* routing
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*/
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if (!(hdr->flags & (GRE_VERSION|GRE_ROUTING))) {
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proto = hdr->proto;
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nhoff += 4;
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if (hdr->flags & GRE_CSUM)
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nhoff += 4;
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if (hdr->flags & GRE_KEY)
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nhoff += 4;
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if (hdr->flags & GRE_SEQ)
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nhoff += 4;
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if (proto == htons(ETH_P_TEB)) {
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const struct ethhdr *eth;
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struct ethhdr _eth;
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eth = skb_header_pointer(skb, nhoff,
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sizeof(_eth), &_eth);
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if (!eth)
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return false;
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proto = eth->h_proto;
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nhoff += sizeof(*eth);
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}
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goto again;
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}
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break;
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}
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case IPPROTO_IPIP:
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proto = htons(ETH_P_IP);
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goto ip;
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case IPPROTO_IPV6:
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proto = htons(ETH_P_IPV6);
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goto ipv6;
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default:
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break;
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}
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flow->ip_proto = ip_proto;
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poff = proto_ports_offset(ip_proto);
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if (poff >= 0) {
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__be32 *ports, _ports;
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nhoff += poff;
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ports = skb_header_pointer(skb, nhoff, sizeof(_ports), &_ports);
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if (ports)
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flow->ports = *ports;
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}
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flow->thoff = (u16) nhoff;
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return true;
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}
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EXPORT_SYMBOL(skb_flow_dissect);
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static u32 hashrnd __read_mostly;
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/*
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* __skb_get_rxhash: calculate a flow hash based on src/dst addresses
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* and src/dst port numbers. Sets rxhash in skb to non-zero hash value
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* on success, zero indicates no valid hash. Also, sets l4_rxhash in skb
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* if hash is a canonical 4-tuple hash over transport ports.
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*/
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void __skb_get_rxhash(struct sk_buff *skb)
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{
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struct flow_keys keys;
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u32 hash;
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if (!skb_flow_dissect(skb, &keys))
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return;
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if (keys.ports)
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skb->l4_rxhash = 1;
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/* get a consistent hash (same value on both flow directions) */
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if (((__force u32)keys.dst < (__force u32)keys.src) ||
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(((__force u32)keys.dst == (__force u32)keys.src) &&
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((__force u16)keys.port16[1] < (__force u16)keys.port16[0]))) {
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swap(keys.dst, keys.src);
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swap(keys.port16[0], keys.port16[1]);
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}
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hash = jhash_3words((__force u32)keys.dst,
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(__force u32)keys.src,
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(__force u32)keys.ports, hashrnd);
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if (!hash)
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hash = 1;
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skb->rxhash = hash;
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}
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EXPORT_SYMBOL(__skb_get_rxhash);
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/*
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* Returns a Tx hash based on the given packet descriptor a Tx queues' number
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* to be used as a distribution range.
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*/
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u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
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unsigned int num_tx_queues)
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{
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u32 hash;
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u16 qoffset = 0;
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u16 qcount = num_tx_queues;
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if (skb_rx_queue_recorded(skb)) {
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hash = skb_get_rx_queue(skb);
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while (unlikely(hash >= num_tx_queues))
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hash -= num_tx_queues;
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return hash;
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}
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if (dev->num_tc) {
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u8 tc = netdev_get_prio_tc_map(dev, skb->priority);
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qoffset = dev->tc_to_txq[tc].offset;
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qcount = dev->tc_to_txq[tc].count;
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}
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if (skb->sk && skb->sk->sk_hash)
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hash = skb->sk->sk_hash;
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else
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hash = (__force u16) skb->protocol;
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hash = jhash_1word(hash, hashrnd);
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return (u16) (((u64) hash * qcount) >> 32) + qoffset;
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}
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EXPORT_SYMBOL(__skb_tx_hash);
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/* __skb_get_poff() returns the offset to the payload as far as it could
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* be dissected. The main user is currently BPF, so that we can dynamically
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* truncate packets without needing to push actual payload to the user
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* space and can analyze headers only, instead.
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*/
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u32 __skb_get_poff(const struct sk_buff *skb)
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{
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struct flow_keys keys;
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u32 poff = 0;
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if (!skb_flow_dissect(skb, &keys))
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return 0;
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poff += keys.thoff;
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switch (keys.ip_proto) {
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case IPPROTO_TCP: {
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const struct tcphdr *tcph;
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struct tcphdr _tcph;
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tcph = skb_header_pointer(skb, poff, sizeof(_tcph), &_tcph);
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if (!tcph)
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return poff;
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poff += max_t(u32, sizeof(struct tcphdr), tcph->doff * 4);
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break;
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}
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case IPPROTO_UDP:
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case IPPROTO_UDPLITE:
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poff += sizeof(struct udphdr);
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break;
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/* For the rest, we do not really care about header
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* extensions at this point for now.
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*/
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case IPPROTO_ICMP:
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poff += sizeof(struct icmphdr);
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break;
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case IPPROTO_ICMPV6:
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poff += sizeof(struct icmp6hdr);
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break;
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case IPPROTO_IGMP:
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poff += sizeof(struct igmphdr);
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break;
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case IPPROTO_DCCP:
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poff += sizeof(struct dccp_hdr);
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break;
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case IPPROTO_SCTP:
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poff += sizeof(struct sctphdr);
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break;
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}
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return poff;
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}
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static inline u16 dev_cap_txqueue(struct net_device *dev, u16 queue_index)
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{
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if (unlikely(queue_index >= dev->real_num_tx_queues)) {
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net_warn_ratelimited("%s selects TX queue %d, but real number of TX queues is %d\n",
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dev->name, queue_index,
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dev->real_num_tx_queues);
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return 0;
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}
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return queue_index;
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}
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static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
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{
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#ifdef CONFIG_XPS
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struct xps_dev_maps *dev_maps;
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struct xps_map *map;
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int queue_index = -1;
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rcu_read_lock();
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dev_maps = rcu_dereference(dev->xps_maps);
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if (dev_maps) {
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map = rcu_dereference(
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dev_maps->cpu_map[raw_smp_processor_id()]);
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if (map) {
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if (map->len == 1)
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queue_index = map->queues[0];
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else {
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u32 hash;
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if (skb->sk && skb->sk->sk_hash)
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hash = skb->sk->sk_hash;
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else
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hash = (__force u16) skb->protocol ^
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skb->rxhash;
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hash = jhash_1word(hash, hashrnd);
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queue_index = map->queues[
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((u64)hash * map->len) >> 32];
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}
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if (unlikely(queue_index >= dev->real_num_tx_queues))
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queue_index = -1;
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}
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}
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rcu_read_unlock();
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return queue_index;
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#else
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return -1;
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#endif
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}
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u16 __netdev_pick_tx(struct net_device *dev, struct sk_buff *skb)
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{
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struct sock *sk = skb->sk;
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int queue_index = sk_tx_queue_get(sk);
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if (queue_index < 0 || skb->ooo_okay ||
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queue_index >= dev->real_num_tx_queues) {
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int new_index = get_xps_queue(dev, skb);
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if (new_index < 0)
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new_index = skb_tx_hash(dev, skb);
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if (queue_index != new_index && sk &&
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rcu_access_pointer(sk->sk_dst_cache))
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sk_tx_queue_set(sk, new_index);
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queue_index = new_index;
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}
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return queue_index;
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}
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EXPORT_SYMBOL(__netdev_pick_tx);
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struct netdev_queue *netdev_pick_tx(struct net_device *dev,
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struct sk_buff *skb)
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{
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int queue_index = 0;
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if (dev->real_num_tx_queues != 1) {
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const struct net_device_ops *ops = dev->netdev_ops;
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if (ops->ndo_select_queue)
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queue_index = ops->ndo_select_queue(dev, skb);
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else
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queue_index = __netdev_pick_tx(dev, skb);
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queue_index = dev_cap_txqueue(dev, queue_index);
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}
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skb_set_queue_mapping(skb, queue_index);
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return netdev_get_tx_queue(dev, queue_index);
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}
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static int __init initialize_hashrnd(void)
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{
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get_random_bytes(&hashrnd, sizeof(hashrnd));
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return 0;
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}
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late_initcall_sync(initialize_hashrnd);
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