From: Eric Dumazet <eduma...@google.com>
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_example02.c
to add TOS reflection ;)
Fixes: f02db315b8d8 ("ipv4: IP_TOS and IP_TTL can be specified as ancillary
data")
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Francesco Fusco <ffu...@redhat.com>
Cc: Jesper Dangaard Brouer <bro...@redhat.com>
---
net/ipv4/ip_sockglue.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index
71a52f4d4cffba2db9353f43dc817689bf4fab10..af4919792b6a812041dcb18ff30aa8b27482c7a2
100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -284,9 +284,12 @@ int ip_cmsg_send(struct sock *sk, struct msghdr *msg,
struct ipcm_cookie *ipc,
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;
