Hello sctp folks,
sctp regression suite is currently broken due to test_1_to_1_sockopt.
Problem is following:
TEST17 sets SO_SNDBUF to 2048
TEST18 gets SO_SNDBUF, expected is 2x2048, but obtained value is 4480
> test_1_to_1_sockopt.c 17 PASS : setsockopt() SO_SNDBUF - SUCCESS
> test_1_to_1_sockopt.c 18 PASS : getsockopt() SO_SNDBUF - SUCCESS
> test_1_to_1_sockopt.c 19 BROK : Comparison failed:Set value and got value differs Set Value=4096 Get Value=4480
reason lies is net/core/sock.c
> case SO_SNDBUF:
> /* Don't error on this BSD doesn't and if you think
> * about it this is right. Otherwise apps have to
> * play 'guess the biggest size' games. RCVBUF/SNDBUF
> * are treated in BSD as hints
> */
> val = min_t(u32, val, sysctl_wmem_max);
> set_sndbuf:
> sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
> sk->sk_sndbuf = max_t(u32, val * 2, SOCK_MIN_SNDBUF);
since SOCK_MIN_SNDBUF is defined as:
include/net/sock.h
> /* Since sk_{r,w}mem_alloc sums skb->truesize, even a small frame might
> * need sizeof(sk_buff) + MTU + padding, unless net driver perform copybreak.
> * Note: for send buffers, TCP works better if we can build two skbs at
> * minimum.
> */
> #define TCP_SKB_MIN_TRUESIZE (2048 + SKB_DATA_ALIGN(sizeof(struct sk_buff)))
>
> #define SOCK_MIN_SNDBUF (TCP_SKB_MIN_TRUESIZE * 2)
> #define SOCK_MIN_RCVBUF TCP_SKB_MIN_TRUESIZE
we can observe that value for which we set SO_SNDBUF in TEST17 in test_1_to_1_sockopt.c needs to be increased
Version is visible in subject, 1.0.15, I hope http://sourceforge.net/projects/lksctp/files/ is still valid place to get it.
Best regards,
Matija
PS: happy new year!
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