From: Eric Dumazet edumazet@google.com
commit e895cdce683161081e3626c4f5a5c55cb72089f8 upstream.
In commit f02db315b8d8 ("ipv4: IP_TOS and IP_TTL can be specified as ancillary data") Francesco added IP_TOS values specified as integer.
However, kernel sends to userspace (at recvmsg() time) an IP_TOS value in a single byte, when IP_RECVTOS is set on the socket.
It can be very useful to reflect all ancillary options as given by the kernel in a subsequent sendmsg(), instead of aborting the sendmsg() with EINVAL after Francesco patch.
So this patch extends IP_TOS ancillary to accept an u8, so that an UDP server can simply reuse same ancillary block without having to mangle it.
Jesper can then augment https://github.com/netoptimizer/network-testing/blob/master/src/udp_example0... to add TOS reflection ;)
Fixes: f02db315b8d8 ("ipv4: IP_TOS and IP_TTL can be specified as ancillary data") Signed-off-by: Eric Dumazet edumazet@google.com Cc: Francesco Fusco ffusco@redhat.com Cc: Jesper Dangaard Brouer brouer@redhat.com Acked-by: Jesper Dangaard Brouer brouer@redhat.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/ipv4/ip_sockglue.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)
--- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -279,9 +279,12 @@ int ip_cmsg_send(struct net *net, struct ipc->ttl = val; break; case IP_TOS: - if (cmsg->cmsg_len != CMSG_LEN(sizeof(int))) + if (cmsg->cmsg_len == CMSG_LEN(sizeof(int))) + val = *(int *)CMSG_DATA(cmsg); + else if (cmsg->cmsg_len == CMSG_LEN(sizeof(u8))) + val = *(u8 *)CMSG_DATA(cmsg); + else return -EINVAL; - val = *(int *)CMSG_DATA(cmsg); if (val < 0 || val > 255) return -EINVAL; ipc->tos = val;