ip: support SO_MARK cmsg

Enable setting skb->mark for UDP and RAW sockets using cmsg.

This is analogous to existing support for TOS, TTL, txtime, etc.

Packet sockets already support this as of commit c7d39e32632e
("packet: support per-packet fwmark for af_packet sendmsg").

Similar to other fields, implement by
1. initialize the sockcm_cookie.mark from socket option sk_mark
2. optionally overwrite this in ip_cmsg_send/ip6_datagram_send_ctl
3. initialize inet_cork.mark from sockcm_cookie.mark
4. initialize each (usually just one) skb->mark from inet_cork.mark

Step 1 is handled in one location for most protocols by ipcm_init_sk
as of commit 351782067b6b ("ipv4: ipcm_cookie initializers").

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 7 insertions, 3 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 8e49fd62eea9..89a4c7c2e25d 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -1294,6 +1294,7 @@ static int ip6_setup_cork(struct sock *sk, struct inet_cork_full *cork,
         cork->base.fragsize = mtu;
         cork->base.gso_size = ipc6->gso_size;
         cork->base.tx_flags = 0;
+        cork->base.mark = ipc6->sockc.mark;
         sock_tx_timestamp(sk, ipc6->sockc.tsflags, &cork->base.tx_flags);
 
         if (dst_allfrag(xfrm_dst_path(&rt->dst)))
@@ -1764,7 +1765,7 @@ struct sk_buff *__ip6_make_skb(struct sock *sk,
         hdr->daddr = *final_dst;
 
         skb->priority = sk->sk_priority;
-        skb->mark = sk->sk_mark;
+        skb->mark = cork->base.mark;
 
         skb->tstamp = cork->base.transmit_time;
 
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 8a6131991e38..6e1888ee4036 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -646,7 +646,7 @@ static int rawv6_send_hdrinc(struct sock *sk, struct msghdr *msg, int length,
 
         skb->protocol = htons(ETH_P_IPV6);
         skb->priority = sk->sk_priority;
-        skb->mark = sk->sk_mark;
+        skb->mark = sockc->mark;
         skb->tstamp = sockc->transmit_time;
 
         skb_put(skb, length);
@@ -810,6 +810,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
 
         ipcm6_init(&ipc6);
         ipc6.sockc.tsflags = sk->sk_tsflags;
+        ipc6.sockc.mark = sk->sk_mark;
 
         if (sin6) {
                 if (addr_len < SIN6_LEN_RFC2133)
@@ -891,6 +892,7 @@ static int rawv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
         opt = ipv6_fixup_options(&opt_space, opt);
 
         fl6.flowi6_proto = proto;
+        fl6.flowi6_mark = ipc6.sockc.mark;
 
         if (!hdrincl) {
                 rfv.msg = msg;
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 827fe7385078..2c8beb3896d1 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1230,6 +1230,7 @@ int udpv6_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
         ipcm6_init(&ipc6);
         ipc6.gso_size = up->gso_size;
         ipc6.sockc.tsflags = sk->sk_tsflags;
+        ipc6.sockc.mark = sk->sk_mark;
 
         /* destination address check */
         if (sin6) {
@@ -1352,7 +1353,7 @@ do_udp_sendmsg:
         if (!fl6.flowi6_oif)
                 fl6.flowi6_oif = np->sticky_pktinfo.ipi6_ifindex;
 
-        fl6.flowi6_mark = sk->sk_mark;
+        fl6.flowi6_mark = ipc6.sockc.mark;
         fl6.flowi6_uid = sk->sk_uid;
 
         if (msg->msg_controllen) {