-u_long tcp_sendspace = 1024*16;
-SYSCTL_INT(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace,
- CTLFLAG_RW, &tcp_sendspace , 0, "");
-u_long tcp_recvspace = 1024*16;
-SYSCTL_INT(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace,
- CTLFLAG_RW, &tcp_recvspace , 0, "");
+u_int32_t tcp_sendspace = 1448*256;
+u_int32_t tcp_recvspace = 1448*384;
+
+/* During attach, the size of socket buffer allocated is limited to
+ * sb_max in sbreserve. Disallow setting the tcp send and recv space
+ * to be more than sb_max because that will cause tcp_attach to fail
+ * (see radar 5713060)
+ */
+static int
+sysctl_tcp_sospace(struct sysctl_oid *oidp, __unused void *arg1,
+ __unused int arg2, struct sysctl_req *req) {
+ u_int32_t new_value = 0, *space_p = NULL;
+ int changed = 0, error = 0;
+ u_quad_t sb_effective_max = (sb_max / (MSIZE+MCLBYTES)) * MCLBYTES;
+
+ switch (oidp->oid_number) {
+ case TCPCTL_SENDSPACE:
+ space_p = &tcp_sendspace;
+ break;
+ case TCPCTL_RECVSPACE:
+ space_p = &tcp_recvspace;
+ break;
+ default:
+ return EINVAL;
+ }
+ error = sysctl_io_number(req, *space_p, sizeof(u_int32_t),
+ &new_value, &changed);
+ if (changed) {
+ if (new_value > 0 && new_value <= sb_effective_max) {
+ *space_p = new_value;
+ } else {
+ error = ERANGE;
+ }
+ }
+ return error;
+}
+
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_SENDSPACE, sendspace, CTLTYPE_INT | CTLFLAG_RW,
+ &tcp_sendspace , 0, &sysctl_tcp_sospace, "IU", "Maximum outgoing TCP datagram size");
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_RECVSPACE, recvspace, CTLTYPE_INT | CTLFLAG_RW,
+ &tcp_recvspace , 0, &sysctl_tcp_sospace, "IU", "Maximum incoming TCP datagram size");
+