diff options
Diffstat (limited to 'net/ipv4/ip_forward.c')
| -rw-r--r-- | net/ipv4/ip_forward.c | 87 |
1 files changed, 59 insertions, 28 deletions
diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c index 0923add122b..3a83ce5efa8 100644 --- a/net/ipv4/ip_forward.c +++ b/net/ipv4/ip_forward.c @@ -4,15 +4,13 @@ * interface as the means of communication with the user level. * * The IP forwarding functionality. - * - * Version: $Id: ip_forward.c,v 1.48 2000/12/13 18:31:48 davem Exp $ * * Authors: see ip.c * * Fixes: - * Many : Split from ip.c , see ip_input.c for + * Many : Split from ip.c , see ip_input.c for * history. - * Dave Gregorich : NULL ip_rt_put fix for multicast + * Dave Gregorich : NULL ip_rt_put fix for multicast * routing. * Jos Vos : Add call_out_firewall before sending, * use output device for accounting. @@ -21,14 +19,13 @@ * Mike McLagan : Routing by source */ -#include <linux/config.h> #include <linux/types.h> #include <linux/mm.h> -#include <linux/sched.h> #include <linux/skbuff.h> #include <linux/ip.h> #include <linux/icmp.h> #include <linux/netdevice.h> +#include <linux/slab.h> #include <net/sock.h> #include <net/ip.h> #include <net/tcp.h> @@ -42,11 +39,30 @@ #include <net/route.h> #include <net/xfrm.h> -static inline int ip_forward_finish(struct sk_buff *skb) +static bool ip_may_fragment(const struct sk_buff *skb) { - struct ip_options * opt = &(IPCB(skb)->opt); + return unlikely((ip_hdr(skb)->frag_off & htons(IP_DF)) == 0) || + skb->ignore_df; +} + +static bool ip_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu) +{ + if (skb->len <= mtu) + return false; + + if (skb_is_gso(skb) && skb_gso_network_seglen(skb) <= mtu) + return false; + + return true; +} + - IP_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS); +static int ip_forward_finish(struct sk_buff *skb) +{ + struct ip_options *opt = &(IPCB(skb)->opt); + + IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_OUTFORWDATAGRAMS); + IP_ADD_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_OUTOCTETS, skb->len); if (unlikely(opt->optlen)) ip_forward_options(skb); @@ -56,9 +72,17 @@ static inline int ip_forward_finish(struct sk_buff *skb) int ip_forward(struct sk_buff *skb) { + u32 mtu; struct iphdr *iph; /* Our header */ struct rtable *rt; /* Route we use */ - struct ip_options * opt = &(IPCB(skb)->opt); + struct ip_options *opt = &(IPCB(skb)->opt); + + /* that should never happen */ + if (skb->pkt_type != PACKET_HOST) + goto drop; + + if (skb_warn_if_lro(skb)) + goto drop; if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb)) goto drop; @@ -66,31 +90,37 @@ int ip_forward(struct sk_buff *skb) if (IPCB(skb)->opt.router_alert && ip_call_ra_chain(skb)) return NET_RX_SUCCESS; - if (skb->pkt_type != PACKET_HOST) - goto drop; + skb_forward_csum(skb); - skb->ip_summed = CHECKSUM_NONE; - /* * According to the RFC, we must first decrease the TTL field. If * that reaches zero, we must reply an ICMP control message telling * that the packet's lifetime expired. */ - if (skb->nh.iph->ttl <= 1) - goto too_many_hops; + if (ip_hdr(skb)->ttl <= 1) + goto too_many_hops; if (!xfrm4_route_forward(skb)) goto drop; - rt = (struct rtable*)skb->dst; + rt = skb_rtable(skb); - if (opt->is_strictroute && rt->rt_dst != rt->rt_gateway) + if (opt->is_strictroute && rt->rt_uses_gateway) goto sr_failed; + IPCB(skb)->flags |= IPSKB_FORWARDED; + mtu = ip_dst_mtu_maybe_forward(&rt->dst, true); + if (!ip_may_fragment(skb) && ip_exceeds_mtu(skb, mtu)) { + IP_INC_STATS(dev_net(rt->dst.dev), IPSTATS_MIB_FRAGFAILS); + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, + htonl(mtu)); + goto drop; + } + /* We are about to mangle packet. Copy it! */ - if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+rt->u.dst.header_len)) + if (skb_cow(skb, LL_RESERVED_SPACE(rt->dst.dev)+rt->dst.header_len)) goto drop; - iph = skb->nh.iph; + iph = ip_hdr(skb); /* Decrease ttl after skb cow done */ ip_decrease_ttl(iph); @@ -99,24 +129,25 @@ int ip_forward(struct sk_buff *skb) * We now generate an ICMP HOST REDIRECT giving the route * we calculated. */ - if (rt->rt_flags&RTCF_DOREDIRECT && !opt->srr) + if (rt->rt_flags&RTCF_DOREDIRECT && !opt->srr && !skb_sec_path(skb)) ip_rt_send_redirect(skb); skb->priority = rt_tos2priority(iph->tos); - return NF_HOOK(PF_INET, NF_IP_FORWARD, skb, skb->dev, rt->u.dst.dev, - ip_forward_finish); + return NF_HOOK(NFPROTO_IPV4, NF_INET_FORWARD, skb, skb->dev, + rt->dst.dev, ip_forward_finish); sr_failed: - /* + /* * Strict routing permits no gatewaying */ - icmp_send(skb, ICMP_DEST_UNREACH, ICMP_SR_FAILED, 0); - goto drop; + icmp_send(skb, ICMP_DEST_UNREACH, ICMP_SR_FAILED, 0); + goto drop; too_many_hops: - /* Tell the sender its packet died... */ - icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0); + /* Tell the sender its packet died... */ + IP_INC_STATS_BH(dev_net(skb_dst(skb)->dev), IPSTATS_MIB_INHDRERRORS); + icmp_send(skb, ICMP_TIME_EXCEEDED, ICMP_EXC_TTL, 0); drop: kfree_skb(skb); return NET_RX_DROP; |