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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /net/ipv4/ip_forward.c | |
download | linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.bz2 linux-3.10-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.zip |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'net/ipv4/ip_forward.c')
-rw-r--r-- | net/ipv4/ip_forward.c | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/net/ipv4/ip_forward.c b/net/ipv4/ip_forward.c new file mode 100644 index 00000000000..77094aac6c2 --- /dev/null +++ b/net/ipv4/ip_forward.c @@ -0,0 +1,127 @@ +/* + * INET An implementation of the TCP/IP protocol suite for the LINUX + * operating system. INET is implemented using the BSD Socket + * 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 + * history. + * Dave Gregorich : NULL ip_rt_put fix for multicast + * routing. + * Jos Vos : Add call_out_firewall before sending, + * use output device for accounting. + * Jos Vos : Call forward firewall after routing + * (always use output device). + * 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 <net/sock.h> +#include <net/ip.h> +#include <net/tcp.h> +#include <net/udp.h> +#include <net/icmp.h> +#include <linux/tcp.h> +#include <linux/udp.h> +#include <linux/netfilter_ipv4.h> +#include <net/checksum.h> +#include <linux/route.h> +#include <net/route.h> +#include <net/xfrm.h> + +static inline int ip_forward_finish(struct sk_buff *skb) +{ + struct ip_options * opt = &(IPCB(skb)->opt); + + IP_INC_STATS_BH(IPSTATS_MIB_OUTFORWDATAGRAMS); + + if (unlikely(opt->optlen)) + ip_forward_options(skb); + + return dst_output(skb); +} + +int ip_forward(struct sk_buff *skb) +{ + struct iphdr *iph; /* Our header */ + struct rtable *rt; /* Route we use */ + struct ip_options * opt = &(IPCB(skb)->opt); + + if (!xfrm4_policy_check(NULL, XFRM_POLICY_FWD, skb)) + goto drop; + + if (IPCB(skb)->opt.router_alert && ip_call_ra_chain(skb)) + return NET_RX_SUCCESS; + + if (skb->pkt_type != PACKET_HOST) + goto drop; + + 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. + */ + + iph = skb->nh.iph; + + if (iph->ttl <= 1) + goto too_many_hops; + + if (!xfrm4_route_forward(skb)) + goto drop; + + iph = skb->nh.iph; + rt = (struct rtable*)skb->dst; + + if (opt->is_strictroute && rt->rt_dst != rt->rt_gateway) + goto sr_failed; + + /* We are about to mangle packet. Copy it! */ + if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+rt->u.dst.header_len)) + goto drop; + iph = skb->nh.iph; + + /* Decrease ttl after skb cow done */ + ip_decrease_ttl(iph); + + /* + * We now generate an ICMP HOST REDIRECT giving the route + * we calculated. + */ + if (rt->rt_flags&RTCF_DOREDIRECT && !opt->srr) + 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); + +sr_failed: + /* + * Strict routing permits no gatewaying + */ + 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); +drop: + kfree_skb(skb); + return NET_RX_DROP; +} |