diff options
Diffstat (limited to 'net/ipv4/netfilter.c')
-rw-r--r-- | net/ipv4/netfilter.c | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c new file mode 100644 index 000000000..bd1351654 --- /dev/null +++ b/net/ipv4/netfilter.c @@ -0,0 +1,95 @@ +/* + * IPv4 specific functions of netfilter core + * + * Rusty Russell (C) 2000 -- This code is GPL. + * Patrick McHardy (C) 2006-2012 + */ +#include <linux/kernel.h> +#include <linux/netfilter.h> +#include <linux/netfilter_ipv4.h> +#include <linux/ip.h> +#include <linux/skbuff.h> +#include <linux/gfp.h> +#include <linux/export.h> +#include <net/route.h> +#include <net/xfrm.h> +#include <net/ip.h> +#include <net/netfilter/nf_queue.h> + +/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */ +int ip_route_me_harder(struct net *net, struct sock *sk, struct sk_buff *skb, unsigned int addr_type) +{ + const struct iphdr *iph = ip_hdr(skb); + struct rtable *rt; + struct flowi4 fl4 = {}; + __be32 saddr = iph->saddr; + __u8 flags; + struct net_device *dev = skb_dst(skb)->dev; + struct flow_keys flkeys; + unsigned int hh_len; + + sk = sk_to_full_sk(sk); + flags = sk ? inet_sk_flowi_flags(sk) : 0; + + if (addr_type == RTN_UNSPEC) + addr_type = inet_addr_type_dev_table(net, dev, saddr); + if (addr_type == RTN_LOCAL || addr_type == RTN_UNICAST) + flags |= FLOWI_FLAG_ANYSRC; + else + saddr = 0; + + /* some non-standard hacks like ipt_REJECT.c:send_reset() can cause + * packets with foreign saddr to appear on the NF_INET_LOCAL_OUT hook. + */ + fl4.daddr = iph->daddr; + fl4.saddr = saddr; + fl4.flowi4_tos = RT_TOS(iph->tos); + fl4.flowi4_oif = sk ? sk->sk_bound_dev_if : 0; + fl4.flowi4_l3mdev = l3mdev_master_ifindex(dev); + fl4.flowi4_mark = skb->mark; + fl4.flowi4_flags = flags; + fib4_rules_early_flow_dissect(net, skb, &fl4, &flkeys); + rt = ip_route_output_key(net, &fl4); + if (IS_ERR(rt)) + return PTR_ERR(rt); + + /* Drop old route. */ + skb_dst_drop(skb); + skb_dst_set(skb, &rt->dst); + + if (skb_dst(skb)->error) + return skb_dst(skb)->error; + +#ifdef CONFIG_XFRM + if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) && + xfrm_decode_session(skb, flowi4_to_flowi(&fl4), AF_INET) == 0) { + struct dst_entry *dst = skb_dst(skb); + skb_dst_set(skb, NULL); + dst = xfrm_lookup(net, dst, flowi4_to_flowi(&fl4), sk, 0); + if (IS_ERR(dst)) + return PTR_ERR(dst); + skb_dst_set(skb, dst); + } +#endif + + /* Change in oif may mean change in hh_len. */ + hh_len = skb_dst(skb)->dev->hard_header_len; + if (skb_headroom(skb) < hh_len && + pskb_expand_head(skb, HH_DATA_ALIGN(hh_len - skb_headroom(skb)), + 0, GFP_ATOMIC)) + return -ENOMEM; + + return 0; +} +EXPORT_SYMBOL(ip_route_me_harder); + +int nf_ip_route(struct net *net, struct dst_entry **dst, struct flowi *fl, + bool strict __always_unused) +{ + struct rtable *rt = ip_route_output_key(net, &fl->u.ip4); + if (IS_ERR(rt)) + return PTR_ERR(rt); + *dst = &rt->dst; + return 0; +} +EXPORT_SYMBOL_GPL(nf_ip_route); |