tcp: pass fl6 to inet6_csk_route_req()

This commit changes inet_csk_route_req() so that it uses a pointer to
a struct flowi6, rather than allocating its own on the stack. This
brings its behavior in line with its IPv4 cousin,
inet_csk_route_req(), and allows a follow-on patch to fix a dst leak.

Signed-off-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 20 insertions, 16 deletions

diff --git a/include/net/inet6_connection_sock.h b/include/net/inet6_connection_sock.h
index 1866a676c810..df2a857e853d 100644
--- a/include/net/inet6_connection_sock.h
+++ b/include/net/inet6_connection_sock.h
@@ -26,6 +26,7 @@ extern int inet6_csk_bind_conflict(const struct sock *sk,
                                    const struct inet_bind_bucket *tb, bool relax);
 
 extern struct dst_entry* inet6_csk_route_req(struct sock *sk,
+                                             struct flowi6 *fl6,
                                              const struct request_sock *req);
 
 extern struct request_sock *inet6_csk_search_req(const struct sock *sk,
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index e23d35424ca9..bceb14450a1d 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -55,26 +55,26 @@ int inet6_csk_bind_conflict(const struct sock *sk,
 EXPORT_SYMBOL_GPL(inet6_csk_bind_conflict);
 
 struct dst_entry *inet6_csk_route_req(struct sock *sk,
+                                      struct flowi6 *fl6,
                                       const struct request_sock *req)
 {
         struct inet6_request_sock *treq = inet6_rsk(req);
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct in6_addr *final_p, final;
         struct dst_entry *dst;
-        struct flowi6 fl6;
-
-        memset(&fl6, 0, sizeof(fl6));
-        fl6.flowi6_proto = IPPROTO_TCP;
-        fl6.daddr = treq->rmt_addr;
-        final_p = fl6_update_dst(&fl6, np->opt, &final);
-        fl6.saddr = treq->loc_addr;
-        fl6.flowi6_oif = treq->iif;
-        fl6.flowi6_mark = sk->sk_mark;
-        fl6.fl6_dport = inet_rsk(req)->rmt_port;
-        fl6.fl6_sport = inet_rsk(req)->loc_port;
-        security_req_classify_flow(req, flowi6_to_flowi(&fl6));
 
-        dst = ip6_dst_lookup_flow(sk, &fl6, final_p, false);
+        memset(fl6, 0, sizeof(*fl6));
+        fl6->flowi6_proto = IPPROTO_TCP;
+        fl6->daddr = treq->rmt_addr;
+        final_p = fl6_update_dst(fl6, np->opt, &final);
+        fl6->saddr = treq->loc_addr;
+        fl6->flowi6_oif = treq->iif;
+        fl6->flowi6_mark = sk->sk_mark;
+        fl6->fl6_dport = inet_rsk(req)->rmt_port;
+        fl6->fl6_sport = inet_rsk(req)->loc_port;
+        security_req_classify_flow(req, flowi6_to_flowi(fl6));
+
+        dst = ip6_dst_lookup_flow(sk, fl6, final_p, false);
         if (IS_ERR(dst))
                 return NULL;
 
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index fc0b96bf9051..4e5fa5f6ec68 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -477,7 +477,8 @@ out:
 }
 
 
-static int tcp_v6_send_synack(struct sock *sk, struct request_sock *req,
+static int tcp_v6_send_synack(struct sock *sk,
+                              struct request_sock *req,
                               struct request_values *rvp,
                               u16 queue_mapping)
 {
@@ -1058,6 +1059,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
         struct tcp_sock *tp = tcp_sk(sk);
         __u32 isn = TCP_SKB_CB(skb)->when;
         struct dst_entry *dst = NULL;
+        struct flowi6 fl6;
         bool want_cookie = false;
 
         if (skb->protocol == htons(ETH_P_IP))
@@ -1177,7 +1179,7 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
                  */
                 if (tmp_opt.saw_tstamp &&
                     tcp_death_row.sysctl_tw_recycle &&
-                    (dst = inet6_csk_route_req(sk, req)) != NULL &&
+                    (dst = inet6_csk_route_req(sk, &fl6, req)) != NULL &&
                     (peer = rt6_get_peer((struct rt6_info *)dst)) != NULL &&
                     ipv6_addr_equal((struct in6_addr *)peer->daddr.addr.a6,
                                     &treq->rmt_addr)) {
@@ -1247,6 +1249,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
 #ifdef CONFIG_TCP_MD5SIG
         struct tcp_md5sig_key *key;
 #endif
+        struct flowi6 fl6;
 
         if (skb->protocol == htons(ETH_P_IP)) {
                 /*
@@ -1309,7 +1312,7 @@ static struct sock * tcp_v6_syn_recv_sock(struct sock *sk, struct sk_buff *skb,
                 goto out_overflow;
 
         if (!dst) {
-                dst = inet6_csk_route_req(sk, req);
+                dst = inet6_csk_route_req(sk, &fl6, req);
                 if (!dst)
                         goto out;
         }