ip: constify ip_build_and_send_pkt() socket argument

This function is used to build and send SYNACK packets,
possibly on behalf of unlocked listener socket.

Make sure we did not miss a write by making this socket const.

We no longer can use ip_select_ident() and have to either
set iph->id to 0 or directly call __ip_select_ident()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip.h b/include/net/ip.h
index 525dc07789269d0683650476363821f676785f8c..91a6b2c88341b8d691af61db57fe77222d7e144f 100644 (file)
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -100,7 +100,7 @@ int igmp_mc_init(void);
  *     Functions provided by ip.c
  */
 
-int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
+int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
                          __be32 saddr, __be32 daddr,
                          struct ip_options_rcu *opt);
 int ip_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt,

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 09a6b7bb7ea389d078904a24c4ca2b8d8c2e9ccb..06d2c87ed505b04f4502af103cf7c7ef45f9f51e 100644 (file)
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -137,7 +137,7 @@ static inline int ip_select_ttl(struct inet_sock *inet, struct dst_entry *dst)
  *             Add an ip header to a skbuff and send it out.
  *
  */
-int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
+int ip_build_and_send_pkt(struct sk_buff *skb, const struct sock *sk,
                          __be32 saddr, __be32 daddr, struct ip_options_rcu *opt)
 {
        struct inet_sock *inet = inet_sk(sk);
@@ -151,15 +151,17 @@ int ip_build_and_send_pkt(struct sk_buff *skb, struct sock *sk,
        iph->version  = 4;
        iph->ihl      = 5;
        iph->tos      = inet->tos;
-       if (ip_dont_fragment(sk, &rt->dst))
-               iph->frag_off = htons(IP_DF);
-       else
-               iph->frag_off = 0;
        iph->ttl      = ip_select_ttl(inet, &rt->dst);
        iph->daddr    = (opt && opt->opt.srr ? opt->opt.faddr : daddr);
        iph->saddr    = saddr;
        iph->protocol = sk->sk_protocol;
-       ip_select_ident(sock_net(sk), skb, sk);
+       if (ip_dont_fragment(sk, &rt->dst)) {
+               iph->frag_off = htons(IP_DF);
+               iph->id = 0;
+       } else {
+               iph->frag_off = 0;
+               __ip_select_ident(sock_net(sk), iph, 1);
+       }
 
        if (opt && opt->opt.optlen) {
                iph->ihl += opt->opt.optlen>>2;