[NETFILTER]: ipt_REJECT: remove largely duplicate route_reverse function

Use ip_route_me_harder instead, which now allows to specify how we wish
the packet to be routed.

Based on patch by Simon Horman <horms@verge.net.au>.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 19 insertions, 78 deletions

diff --git a/net/ipv4/netfilter/ipt_REJECT.c b/net/ipv4/netfilter/ipt_REJECT.c
index fd0c05efed8a..ad0312d0e4fd 100644
--- a/net/ipv4/netfilter/ipt_REJECT.c
+++ b/net/ipv4/netfilter/ipt_REJECT.c
@@ -38,76 +38,16 @@ MODULE_DESCRIPTION("iptables REJECT target module");
 #define DEBUGP(format, args...)
 #endif
 
-static inline struct rtable *route_reverse(struct sk_buff *skb, 
-                                           struct tcphdr *tcph, int hook)
-{
-        struct iphdr *iph = skb->nh.iph;
-        struct dst_entry *odst;
-        struct flowi fl = {};
-        struct rtable *rt;
-
-        /* We don't require ip forwarding to be enabled to be able to
-         * send a RST reply for bridged traffic. */
-        if (hook != NF_IP_FORWARD
-#ifdef CONFIG_BRIDGE_NETFILTER
-            || (skb->nf_bridge && skb->nf_bridge->mask & BRNF_BRIDGED)
-#endif
-           ) {
-                fl.nl_u.ip4_u.daddr = iph->saddr;
-                if (hook == NF_IP_LOCAL_IN)
-                        fl.nl_u.ip4_u.saddr = iph->daddr;
-                fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
-
-                if (ip_route_output_key(&rt, &fl) != 0)
-                        return NULL;
-        } else {
-                /* non-local src, find valid iif to satisfy
-                 * rp-filter when calling ip_route_input. */
-                fl.nl_u.ip4_u.daddr = iph->daddr;
-                if (ip_route_output_key(&rt, &fl) != 0)
-                        return NULL;
-
-                odst = skb->dst;
-                if (ip_route_input(skb, iph->saddr, iph->daddr,
-                                   RT_TOS(iph->tos), rt->u.dst.dev) != 0) {
-                        dst_release(&rt->u.dst);
-                        return NULL;
-                }
-                dst_release(&rt->u.dst);
-                rt = (struct rtable *)skb->dst;
-                skb->dst = odst;
-
-                fl.nl_u.ip4_u.daddr = iph->saddr;
-                fl.nl_u.ip4_u.saddr = iph->daddr;
-                fl.nl_u.ip4_u.tos = RT_TOS(iph->tos);
-        }
-
-        if (rt->u.dst.error) {
-                dst_release(&rt->u.dst);
-                return NULL;
-        }
-
-        fl.proto = IPPROTO_TCP;
-        fl.fl_ip_sport = tcph->dest;
-        fl.fl_ip_dport = tcph->source;
-        security_skb_classify_flow(skb, &fl);
-
-        xfrm_lookup((struct dst_entry **)&rt, &fl, NULL, 0);
-
-        return rt;
-}
-
 /* Send RST reply */
 static void send_reset(struct sk_buff *oldskb, int hook)
 {
         struct sk_buff *nskb;
         struct iphdr *iph = oldskb->nh.iph;
         struct tcphdr _otcph, *oth, *tcph;
-        struct rtable *rt;
         __be16 tmp_port;
         __be32 tmp_addr;
         int needs_ack;
-        int hh_len;
+        unsigned int addr_type;
 
         /* IP header checks: fragment. */
         if (oldskb->nh.iph->frag_off & htons(IP_OFFSET))
@@ -126,23 +66,13 @@ static void send_reset(struct sk_buff *oldskb, int hook)
         if (nf_ip_checksum(oldskb, hook, iph->ihl * 4, IPPROTO_TCP))
                 return;
 
-        if ((rt = route_reverse(oldskb, oth, hook)) == NULL)
-                return;
-
-        hh_len = LL_RESERVED_SPACE(rt->u.dst.dev);
-
         /* We need a linear, writeable skb.  We also need to expand
            headroom in case hh_len of incoming interface < hh_len of
            outgoing interface */
-        nskb = skb_copy_expand(oldskb, hh_len, skb_tailroom(oldskb),
+        nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb),
                                GFP_ATOMIC);
-        if (!nskb) {
-                dst_release(&rt->u.dst);
+        if (!nskb)
                 return;
-        }
-
-        dst_release(nskb->dst);
-        nskb->dst = &rt->u.dst;
 
         /* This packet will not be the same as the other: clear nf fields */
         nf_reset(nskb);
@@ -184,6 +114,21 @@ static void send_reset(struct sk_buff *oldskb, int hook)
         tcph->window = 0;
         tcph->urg_ptr = 0;
 
+        /* Set DF, id = 0 */
+        nskb->nh.iph->frag_off = htons(IP_DF);
+        nskb->nh.iph->id = 0;
+
+        addr_type = RTN_UNSPEC;
+        if (hook != NF_IP_FORWARD
+#ifdef CONFIG_BRIDGE_NETFILTER
+            || (nskb->nf_bridge && nskb->nf_bridge->mask & BRNF_BRIDGED)
+#endif
+           )
+                addr_type = RTN_LOCAL;
+
+        if (ip_route_me_harder(&nskb, addr_type))
+                goto free_nskb;
+
         /* Adjust TCP checksum */
         nskb->ip_summed = CHECKSUM_NONE;
         tcph->check = 0;
@@ -192,12 +137,8 @@ static void send_reset(struct sk_buff *oldskb, int hook)
                                    nskb->nh.iph->daddr,
                                    csum_partial((char *)tcph,
                                                 sizeof(struct tcphdr), 0));
-
-        /* Adjust IP TTL, DF */
+        /* Adjust IP TTL */
         nskb->nh.iph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
-        /* Set DF, id = 0 */
-        nskb->nh.iph->frag_off = htons(IP_DF);
-        nskb->nh.iph->id = 0;
 
         /* Adjust IP checksum */
         nskb->nh.iph->check = 0;