From: Ondrej Zajicek <santiago@crfreenet.org>
Date: Thu, 1 Aug 2024 12:55:05 +0000 (+0200)
Subject: IO: Ensure that socket rcvbuf is large enough
X-Git-Tag: v2.16~51
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5214d7e59fe4d5d89e14e8e7b654ded25f918afb;p=thirdparty%2Fbird.git

IO: Ensure that socket rcvbuf is large enough

The socket structure has the field rbsize (receive buffer size), which
controls the size of the userspace receive buffer. There is also kernel
receive buffer, which in some cases may be smaller (e.g. on FreeBSD it
is by default ~8k). The patch ensures that the kernel receive buffer is
as large as the userspace receive buffer.
---

diff --git a/sysdep/unix/io.c b/sysdep/unix/io.c
index 987c7a6ba..59b33ef18 100644
--- a/sysdep/unix/io.c
+++ b/sysdep/unix/io.c
@@ -517,6 +517,40 @@ sk_set_high_port(sock *s UNUSED)
   return 0;
 }
 
+static inline int
+sk_set_min_rcvbuf_(sock *s, int bufsize)
+{
+  int oldsize = 0, oldsize_s = sizeof(oldsize);
+
+  if (getsockopt(s->fd, SOL_SOCKET, SO_RCVBUF, &oldsize, &oldsize_s) < 0)
+    ERR("SO_RCVBUF");
+
+  if (oldsize >= bufsize)
+    return 0;
+
+  bufsize = BIRD_ALIGN(bufsize, 64);
+  if (setsockopt(s->fd, SOL_SOCKET, SO_RCVBUF, &bufsize, sizeof(bufsize)) < 0)
+    ERR("SO_RCVBUF");
+
+  /*
+  int newsize = 0, newsize_s = sizeof(newsize);
+  if (getsockopt(s->fd, SOL_SOCKET, SO_RCVBUF, &newsize, &newsize_s) < 0)
+    ERR("SO_RCVBUF");
+
+  log(L_INFO "Setting rcvbuf on %s from %d to %d",
+      s->iface ? s->iface->name : "*", oldsize, newsize);
+  */
+
+  return 0;
+}
+
+static void
+sk_set_min_rcvbuf(sock *s, int bufsize)
+{
+  if (sk_set_min_rcvbuf_(s, bufsize) < 0)
+    log(L_WARN "Socket error: %s%#m", s->err);
+}
+
 static inline byte *
 sk_skip_ip_header(byte *pkt, int *len)
 {
@@ -862,6 +896,9 @@ sk_set_rbsize(sock *s, uint val)
   xfree(s->rbuf_alloc);
   s->rbuf_alloc = xmalloc(val);
   s->rpos = s->rbuf = s->rbuf_alloc;
+
+  if ((s->type == SK_UDP) || (s->type == SK_IP))
+    sk_set_min_rcvbuf(s, s->rbsize);
 }
 
 void
@@ -1058,6 +1095,9 @@ sk_setup(sock *s)
     if (sk_set_priority(s, s->priority) < 0)
       return -1;
 
+  if ((s->type == SK_UDP) || (s->type == SK_IP))
+    sk_set_min_rcvbuf(s, s->rbsize);
+
   return 0;
 }