set MTU on tunnel interface so the kernel will re-fragment large packets to within MRU

[l2tpns.git] / l2tpns.c

diff --git a/l2tpns.c b/l2tpns.c
index 2c452ae..816d27f 100644 (file)
--- a/l2tpns.c
+++ b/l2tpns.c
@@ -4,7 +4,7 @@
 // Copyright (c) 2002 FireBrick (Andrews & Arnold Ltd / Watchfront Ltd) - GPL licenced
 // vim: sw=8 ts=8
 
-char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.148 2005-11-14 21:08:30 bodea Exp $";
+char const *cvs_id_l2tpns = "$Id: l2tpns.c,v 1.150 2005-11-17 07:35:35 bodea Exp $";
 
 #include <arpa/inet.h>
 #include <assert.h>
@@ -554,6 +554,13 @@ static void inittun(void)
                LOG(0, 0, 0, "Error setting tun queue length: %s\n", strerror(errno));
                exit(1);
        }
+       /* set MTU to modem MRU + 4 (tun header) */
+       ifr.ifr_mtu = MRU + 4;
+       if (ioctl(ifrfd, SIOCSIFMTU, (void *) &ifr) < 0)
+       {
+               LOG(0, 0, 0, "Error setting tun MTU: %s\n", strerror(errno));
+               exit(1);
+       }
        ifr.ifr_flags = IFF_UP;
        if (ioctl(ifrfd, SIOCSIFFLAGS, (void *) &ifr) < 0)
        {
@@ -1043,7 +1050,7 @@ void adjust_tcp_mss(sessionidt s, tunnelidt t, uint8_t *buf, int len, uint8_t *t
        sum = orig + (~MSS & 0xffff);
        sum += ntohs(*(uint16_t *) (tcp + 16));
        sum = (sum & 0xffff) + (sum >> 16);
-       *(uint16_t *) (tcp + 16) = htons(sum);
+       *(uint16_t *) (tcp + 16) = htons(sum + (sum >> 16));
 }
 
 // process outgoing (to tunnel) IP
@@ -1170,7 +1177,8 @@ static void processipout(uint8_t *buf, int len)
                        master_throttle_packet(sp->tbf_out, data, size);
                return;
        }
-       else if (sp->walled_garden && !config->cluster_iam_master)
+
+       if (sp->walled_garden && !config->cluster_iam_master)
        {
                // We are walled-gardening this
                master_garden_packet(s, data, size);