ipv4: add a sock pointer to ip_queue_xmit()

ip_queue_xmit() assumes the skb it has to transmit is attached to an
inet socket. Commit 31c70d5956fc ("l2tp: keep original skb ownership")
changed l2tp to not change skb ownership and thus broke this assumption.

One fix is to add a new 'struct sock *sk' parameter to ip_queue_xmit(),
so that we do not assume skb->sk points to the socket used by l2tp
tunnel.

Fixes: 31c70d5956fc ("l2tp: keep original skb ownership")
Reported-by: Zhan Jianyu <nasa4836@gmail.com>
Tested-by: Zhan Jianyu <nasa4836@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/inet6_connection_sock.h b/include/net/inet6_connection_sock.h
index f981ba7..74af137 100644 (file)
--- a/include/net/inet6_connection_sock.h
+++ b/include/net/inet6_connection_sock.h
@@ -40,7 +40,7 @@ void inet6_csk_reqsk_queue_hash_add(struct sock *sk, struct request_sock *req,
 
 void inet6_csk_addr2sockaddr(struct sock *sk, struct sockaddr *uaddr);
 
-int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl);
+int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 
 struct dst_entry *inet6_csk_update_pmtu(struct sock *sk, u32 mtu);
 #endif /* _INET6_CONNECTION_SOCK_H */

diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
index c55aeed..7a43138 100644 (file)
--- a/include/net/inet_connection_sock.h
+++ b/include/net/inet_connection_sock.h
@@ -36,7 +36,7 @@ struct tcp_congestion_ops;
  * (i.e. things that depend on the address family)
  */
 struct inet_connection_sock_af_ops {
-       int         (*queue_xmit)(struct sk_buff *skb, struct flowi *fl);
+       int         (*queue_xmit)(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
        void        (*send_check)(struct sock *sk, struct sk_buff *skb);
        int         (*rebuild_header)(struct sock *sk);
        void        (*sk_rx_dst_set)(struct sock *sk, const struct sk_buff *skb);

diff --git a/include/net/ip.h b/include/net/ip.h
index 25064c2..77e73d2 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -111,7 +111,7 @@ int ip_do_nat(struct sk_buff *skb);
 void ip_send_check(struct iphdr *ip);
 int __ip_local_out(struct sk_buff *skb);
 int ip_local_out(struct sk_buff *skb);
-int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl);
+int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl);
 void ip_init(void);
 int ip_append_data(struct sock *sk, struct flowi4 *fl4,
                   int getfrag(void *from, char *to, int offset, int len,

diff --git a/net/dccp/output.c b/net/dccp/output.c
index 8876078..0248e8a 100644 (file)
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
@@ -138,7 +138,7 @@ static int dccp_transmit_skb(struct sock *sk, struct sk_buff *skb)
 
                DCCP_INC_STATS(DCCP_MIB_OUTSEGS);
 
-               err = icsk->icsk_af_ops->queue_xmit(skb, &inet->cork.fl);
+               err = icsk->icsk_af_ops->queue_xmit(sk, skb, &inet->cork.fl);
                return net_xmit_eval(err);
        }
        return -ENOBUFS;

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 1a0755f..7ad68b8 100644 (file)
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -315,9 +315,9 @@ static void ip_copy_addrs(struct iphdr *iph, const struct flowi4 *fl4)
               sizeof(fl4->saddr) + sizeof(fl4->daddr));
 }
 
-int ip_queue_xmit(struct sk_buff *skb, struct flowi *fl)
+/* Note: skb->sk can be different from sk, in case of tunnels */
+int ip_queue_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl)
 {
-       struct sock *sk = skb->sk;
        struct inet_sock *inet = inet_sk(sk);
        struct ip_options_rcu *inet_opt;
        struct flowi4 *fl4;
@@ -389,6 +389,7 @@ packet_routed:
        ip_select_ident_more(skb, &rt->dst, sk,
                             (skb_shinfo(skb)->gso_segs ?: 1) - 1);
 
+       /* TODO : should we use skb->sk here instead of sk ? */
        skb->priority = sk->sk_priority;
        skb->mark = sk->sk_mark;
 

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 699fb10..025e250 100644 (file)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -981,7 +981,7 @@ static int tcp_transmit_skb(struct sock *sk, struct sk_buff *skb, int clone_it,
                TCP_ADD_STATS(sock_net(sk), TCP_MIB_OUTSEGS,
                              tcp_skb_pcount(skb));
 
-       err = icsk->icsk_af_ops->queue_xmit(skb, &inet->cork.fl);
+       err = icsk->icsk_af_ops->queue_xmit(sk, skb, &inet->cork.fl);
        if (likely(err <= 0))
                return err;
 

diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index c913818..d4ade34 100644 (file)
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -224,9 +224,8 @@ static struct dst_entry *inet6_csk_route_socket(struct sock *sk,
        return dst;
 }
 
-int inet6_csk_xmit(struct sk_buff *skb, struct flowi *fl_unused)
+int inet6_csk_xmit(struct sock *sk, struct sk_buff *skb, struct flowi *fl_unused)
 {
-       struct sock *sk = skb->sk;
        struct ipv6_pinfo *np = inet6_sk(sk);
        struct flowi6 fl6;
        struct dst_entry *dst;

diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 47f7a54..a4e37d7 100644 (file)
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -1131,10 +1131,10 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
        skb->local_df = 1;
 #if IS_ENABLED(CONFIG_IPV6)
        if (tunnel->sock->sk_family == PF_INET6 && !tunnel->v4mapped)
-               error = inet6_csk_xmit(skb, NULL);
+               error = inet6_csk_xmit(tunnel->sock, skb, NULL);
        else
 #endif
-               error = ip_queue_xmit(skb, fl);
+               error = ip_queue_xmit(tunnel->sock, skb, fl);
 
        /* Update stats */
        if (error >= 0) {

diff --git a/net/l2tp/l2tp_ip.c b/net/l2tp/l2tp_ip.c
index 0b44d85..3397fe6 100644 (file)
--- a/net/l2tp/l2tp_ip.c
+++ b/net/l2tp/l2tp_ip.c
@@ -487,7 +487,7 @@ static int l2tp_ip_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *m
 
 xmit:
        /* Queue the packet to IP for output */
-       rc = ip_queue_xmit(skb, &inet->cork.fl);
+       rc = ip_queue_xmit(sk, skb, &inet->cork.fl);
        rcu_read_unlock();
 
 error:

diff --git a/net/sctp/protocol.c b/net/sctp/protocol.c
index 4e1d0fc..c09757f 100644 (file)
--- a/net/sctp/protocol.c
+++ b/net/sctp/protocol.c
@@ -957,7 +957,7 @@ static inline int sctp_v4_xmit(struct sk_buff *skb,
 
        SCTP_INC_STATS(sock_net(&inet->sk), SCTP_MIB_OUTSCTPPACKS);
 
-       return ip_queue_xmit(skb, &transport->fl);
+       return ip_queue_xmit(&inet->sk, skb, &transport->fl);
 }
 
 static struct sctp_af sctp_af_inet;