sock: support per-packet fwmark

It's useful to allow users to set fwmark for an individual packet,
without changing the socket state. The function this patch adds in
sock layer can be used by the protocols that need such a feature.

Signed-off-by: Edward Hyunkoo Jee <edjee@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/sock.h b/include/net/sock.h
index 771ca1996442fbf48c8d425cab904acf9c6ede57..9322cafd191b7321d2065461d151acee71bb987c 100644 (file)
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1514,6 +1514,13 @@ void sock_kfree_s(struct sock *sk, void *mem, int size);
 void sock_kzfree_s(struct sock *sk, void *mem, int size);
 void sk_send_sigurg(struct sock *sk);
 
+struct sockcm_cookie {
+       u32 mark;
+};
+
+int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
+                  struct sockcm_cookie *sockc);
+
 /*
  * Functions to fill in entries in struct proto_ops when a protocol
  * does not implement a particular function.

diff --git a/net/core/sock.c b/net/core/sock.c
index 7dd1263e4c245ec203ece2463699b9a6378729a3..33957776cc1af787966bb9f4627a6b7eccc35157 100644 (file)
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1852,6 +1852,32 @@ struct sk_buff *sock_alloc_send_skb(struct sock *sk, unsigned long size,
 }
 EXPORT_SYMBOL(sock_alloc_send_skb);
 
+int sock_cmsg_send(struct sock *sk, struct msghdr *msg,
+                  struct sockcm_cookie *sockc)
+{
+       struct cmsghdr *cmsg;
+
+       for_each_cmsghdr(cmsg, msg) {
+               if (!CMSG_OK(msg, cmsg))
+                       return -EINVAL;
+               if (cmsg->cmsg_level != SOL_SOCKET)
+                       continue;
+               switch (cmsg->cmsg_type) {
+               case SO_MARK:
+                       if (!ns_capable(sock_net(sk)->user_ns, CAP_NET_ADMIN))
+                               return -EPERM;
+                       if (cmsg->cmsg_len != CMSG_LEN(sizeof(u32)))
+                               return -EINVAL;
+                       sockc->mark = *(u32 *)CMSG_DATA(cmsg);
+                       break;
+               default:
+                       return -EINVAL;
+               }
+       }
+       return 0;
+}
+EXPORT_SYMBOL(sock_cmsg_send);
+
 /* On 32bit arches, an skb frag is limited to 2^15 */
 #define SKB_FRAG_PAGE_ORDER    get_order(32768)