tcp: add route_req method to tcp_request_sock_ops

Create wrappers with same signature for the IPv4/IPv6 request routing
calls and use these wrappers (via route_req method from
tcp_request_sock_ops) in tcp_v4_conn_request and tcp_v6_conn_request
with the purpose of unifying the two functions in a later patch.

We can later drop the wrapper functions and modify inet_csk_route_req
and inet6_cks_route_req to use the same signature.

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 52 insertions, 13 deletions

diff --git a/include/net/tcp.h b/include/net/tcp.h
index 086d00ec6d8b..59fcc5934c79 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1605,6 +1605,9 @@ struct tcp_request_sock_ops {
         __u32 (*cookie_init_seq)(struct sock *sk, const struct sk_buff *skb,
                                  __u16 *mss);
 #endif
+        struct dst_entry *(*route_req)(struct sock *sk, struct flowi *fl,
+                                       const struct request_sock *req,
+                                       bool *strict);
 };
 
 #ifdef CONFIG_SYN_COOKIES
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index 8c69e44c287b..54fbbd8b4fcd 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -1248,6 +1248,22 @@ static void tcp_v4_init_req(struct request_sock *req, struct sock *sk,
         ireq->opt = tcp_v4_save_options(skb);
 }
 
+static struct dst_entry *tcp_v4_route_req(struct sock *sk, struct flowi *fl,
+                                          const struct request_sock *req,
+                                          bool *strict)
+{
+        struct dst_entry *dst = inet_csk_route_req(sk, &fl->u.ip4, req);
+
+        if (strict) {
+                if (fl->u.ip4.daddr == inet_rsk(req)->ir_rmt_addr)
+                        *strict = true;
+                else
+                        *strict = false;
+        }
+
+        return dst;
+}
+
 struct request_sock_ops tcp_request_sock_ops __read_mostly = {
         .family         =       PF_INET,
         .obj_size       =       sizeof(struct tcp_request_sock),
@@ -1267,6 +1283,7 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv4_ops = {
 #ifdef CONFIG_SYN_COOKIES
         .cookie_init_seq =      cookie_v4_init_sequence,
 #endif
+        .route_req      =       tcp_v4_route_req,
 };
 
 int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
@@ -1346,11 +1363,13 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
                  * timewait bucket, so that all the necessary checks
                  * are made in the function processing timewait state.
                  */
-                if (tmp_opt.saw_tstamp &&
-                    tcp_death_row.sysctl_tw_recycle &&
-                    (dst = inet_csk_route_req(sk, &fl4, req)) != NULL &&
-                    fl4.daddr == saddr) {
-                        if (!tcp_peer_is_proven(req, dst, true)) {
+                if (tmp_opt.saw_tstamp && tcp_death_row.sysctl_tw_recycle) {
+                        bool strict;
+
+                        dst = af_ops->route_req(sk, (struct flowi *)&fl4, req,
+                                                &strict);
+                        if (dst && strict &&
+                            !tcp_peer_is_proven(req, dst, true)) {
                                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
                                 goto drop_and_release;
                         }
@@ -1374,8 +1393,11 @@ int tcp_v4_conn_request(struct sock *sk, struct sk_buff *skb)
 
                 isn = tcp_v4_init_sequence(skb);
         }
-        if (!dst && (dst = inet_csk_route_req(sk, &fl4, req)) == NULL)
-                goto drop_and_free;
+        if (!dst) {
+                dst = af_ops->route_req(sk, (struct flowi *)&fl4, req, NULL);
+                if (!dst)
+                        goto drop_and_free;
+        }
 
         tcp_rsk(req)->snt_isn = isn;
         tcp_openreq_init_rwin(req, sk, dst);
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 17710cffddaa..d780d8808566 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -745,6 +745,16 @@ static void tcp_v6_init_req(struct request_sock *req, struct sock *sk,
         }
 }
 
+static struct dst_entry *tcp_v6_route_req(struct sock *sk, struct flowi *fl,
+                                          const struct request_sock *req,
+                                          bool *strict)
+{
+        if (strict)
+                *strict = true;
+        return inet6_csk_route_req(sk, &fl->u.ip6, req);
+}
+
+
 struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
         .family         =       AF_INET6,
         .obj_size       =       sizeof(struct tcp6_request_sock),
@@ -764,6 +774,7 @@ static const struct tcp_request_sock_ops tcp_request_sock_ipv6_ops = {
 #ifdef CONFIG_SYN_COOKIES
         .cookie_init_seq =      cookie_v6_init_sequence,
 #endif
+        .route_req      =       tcp_v6_route_req,
 };
 
 static void tcp_v6_send_response(struct sk_buff *skb, u32 seq, u32 ack, u32 win,
@@ -1078,10 +1089,10 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
                  * timewait bucket, so that all the necessary checks
                  * are made in the function processing timewait state.
                  */
-                if (tmp_opt.saw_tstamp &&
-                    tcp_death_row.sysctl_tw_recycle &&
-                    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL) {
-                        if (!tcp_peer_is_proven(req, dst, true)) {
+                if (tmp_opt.saw_tstamp && tcp_death_row.sysctl_tw_recycle) {
+                        dst = af_ops->route_req(sk, (struct flowi *)&fl6, req,
+                                                NULL);
+                        if (dst && !tcp_peer_is_proven(req, dst, true)) {
                                 NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_PAWSPASSIVEREJECTED);
                                 goto drop_and_release;
                         }
@@ -1110,8 +1121,11 @@ have_isn:
         if (security_inet_conn_request(sk, skb, req))
                 goto drop_and_release;
 
-        if (!dst && (dst = inet6_csk_route_req(sk, &fl6, req)) == NULL)
-                goto drop_and_free;
+        if (!dst) {
+                dst = af_ops->route_req(sk, (struct flowi *)&fl6, req, NULL);
+                if (!dst)
+                        goto drop_and_free;
+        }
 
         tcp_rsk(req)->snt_isn = isn;
         tcp_openreq_init_rwin(req, sk, dst);