From 5b943e56d6bc9ac63418686a2206759b325c9705 Mon Sep 17 00:00:00 2001 From: Pablo Neira Ayuso Date: Fri, 20 Sep 2019 17:01:47 +0200 Subject: mnl: do not cache sender buffer size SO_SNDBUF never fails, this socket option just provides a hint to the kernel. SO_SNDBUFFORCE sets the buffer size to zero if the value goes over INT_MAX. Userspace is caching the buffer hint that sends to the kernel, so it might leave userspace out of sync if the kernel ignores the hint. Do not make assumptions, fetch the sender buffer size from the kernel via getsockopt(). Signed-off-by: Pablo Neira Ayuso --- src/mnl.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) (limited to 'src') diff --git a/src/mnl.c b/src/mnl.c index 57ff89f5..14fa4a71 100644 --- a/src/mnl.c +++ b/src/mnl.c @@ -218,24 +218,24 @@ void mnl_err_list_free(struct mnl_err *err) xfree(err); } -static int nlbuffsiz; - static void mnl_set_sndbuffer(const struct mnl_socket *nl, struct nftnl_batch *batch) { + socklen_t len = sizeof(int); + int sndnlbuffsiz = 0; int newbuffsiz; - if (nftnl_batch_iovec_len(batch) * BATCH_PAGE_SIZE <= nlbuffsiz) - return; + getsockopt(mnl_socket_get_fd(nl), SOL_SOCKET, SO_SNDBUF, + &sndnlbuffsiz, &len); newbuffsiz = nftnl_batch_iovec_len(batch) * BATCH_PAGE_SIZE; + if (newbuffsiz <= sndnlbuffsiz) + return; /* Rise sender buffer length to avoid hitting -EMSGSIZE */ if (setsockopt(mnl_socket_get_fd(nl), SOL_SOCKET, SO_SNDBUFFORCE, &newbuffsiz, sizeof(socklen_t)) < 0) return; - - nlbuffsiz = newbuffsiz; } static unsigned int nlsndbufsiz; -- cgit v1.2.3