Harald Welte | 020b4c1 | 2005-08-09 19:39:00 -0700 | [diff] [blame^] | 1 | #include <linux/config.h> |
| 2 | |
| 3 | #ifdef CONFIG_NETFILTER |
| 4 | |
| 5 | /* IPv4 specific functions of netfilter core */ |
| 6 | #include <linux/kernel.h> |
| 7 | #include <linux/netfilter.h> |
| 8 | |
| 9 | #include <linux/tcp.h> |
| 10 | #include <linux/udp.h> |
| 11 | #include <linux/icmp.h> |
| 12 | #include <net/route.h> |
| 13 | #include <linux/ip.h> |
| 14 | |
| 15 | /* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ |
| 16 | int ip_route_me_harder(struct sk_buff **pskb) |
| 17 | { |
| 18 | struct iphdr *iph = (*pskb)->nh.iph; |
| 19 | struct rtable *rt; |
| 20 | struct flowi fl = {}; |
| 21 | struct dst_entry *odst; |
| 22 | unsigned int hh_len; |
| 23 | |
| 24 | /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause |
| 25 | * packets with foreign saddr to appear on the NF_IP_LOCAL_OUT hook. |
| 26 | */ |
| 27 | if (inet_addr_type(iph->saddr) == RTN_LOCAL) { |
| 28 | fl.nl_u.ip4_u.daddr = iph->daddr; |
| 29 | fl.nl_u.ip4_u.saddr = iph->saddr; |
| 30 | fl.nl_u.ip4_u.tos = RT_TOS(iph->tos); |
| 31 | fl.oif = (*pskb)->sk ? (*pskb)->sk->sk_bound_dev_if : 0; |
| 32 | #ifdef CONFIG_IP_ROUTE_FWMARK |
| 33 | fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark; |
| 34 | #endif |
| 35 | fl.proto = iph->protocol; |
| 36 | if (ip_route_output_key(&rt, &fl) != 0) |
| 37 | return -1; |
| 38 | |
| 39 | /* Drop old route. */ |
| 40 | dst_release((*pskb)->dst); |
| 41 | (*pskb)->dst = &rt->u.dst; |
| 42 | } else { |
| 43 | /* non-local src, find valid iif to satisfy |
| 44 | * rp-filter when calling ip_route_input. */ |
| 45 | fl.nl_u.ip4_u.daddr = iph->saddr; |
| 46 | if (ip_route_output_key(&rt, &fl) != 0) |
| 47 | return -1; |
| 48 | |
| 49 | odst = (*pskb)->dst; |
| 50 | if (ip_route_input(*pskb, iph->daddr, iph->saddr, |
| 51 | RT_TOS(iph->tos), rt->u.dst.dev) != 0) { |
| 52 | dst_release(&rt->u.dst); |
| 53 | return -1; |
| 54 | } |
| 55 | dst_release(&rt->u.dst); |
| 56 | dst_release(odst); |
| 57 | } |
| 58 | |
| 59 | if ((*pskb)->dst->error) |
| 60 | return -1; |
| 61 | |
| 62 | /* Change in oif may mean change in hh_len. */ |
| 63 | hh_len = (*pskb)->dst->dev->hard_header_len; |
| 64 | if (skb_headroom(*pskb) < hh_len) { |
| 65 | struct sk_buff *nskb; |
| 66 | |
| 67 | nskb = skb_realloc_headroom(*pskb, hh_len); |
| 68 | if (!nskb) |
| 69 | return -1; |
| 70 | if ((*pskb)->sk) |
| 71 | skb_set_owner_w(nskb, (*pskb)->sk); |
| 72 | kfree_skb(*pskb); |
| 73 | *pskb = nskb; |
| 74 | } |
| 75 | |
| 76 | return 0; |
| 77 | } |
| 78 | EXPORT_SYMBOL(ip_route_me_harder); |
| 79 | #endif /* CONFIG_NETFILTER */ |