Skip to contentSkip to conversation

ppp: change MTU on TUN device when MRU option received

PATCH In review Kristen Carlson Accardi 2 participants 2 messages Apr 22, 2010

lore
Share & tools
lore

Kristen Carlson Accardi

author
#0 lore raw

PATCH 1/1 ppp: change MTU on TUN device when MRU option received

---
 gatchat/ppp_net.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)
gatchat/ppp_net.c +16 -0
index c1f2eb4..fc1f9fb 100644
@@ -50,10 +50,26 @@ struct ppp_net {
 
 void ppp_net_set_mtu(struct ppp_net *net, guint16 mtu)
 {
+	struct ifreq ifr;
+	int sock;
+
 	if (net == NULL)
 		return;
 
 	net->mtu = mtu;
+
+	sock = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sock < 0)
+		return;
+
+	memset(&ifr, 0, sizeof(ifr));
+
+	strncpy(ifr.ifr_name, net->if_name, sizeof(ifr.ifr_name));
+	ifr.ifr_mtu = mtu;
+	if (ioctl(sock, SIOCSIFMTU, (caddr_t) &ifr) < 0)
+		g_printerr("Unable to change MTU\n");
+
+	close(sock);
 }
 
 void ppp_net_process_packet(struct ppp_net *net, guint8 *packet)
Signature · 1 line
1.6.6.1
#1 lore raw

Hi Kristen,

Quoted 14 lines
---
 gatchat/ppp_net.c |   16 ++++++++++++++++
 1 files changed, 16 insertions(+), 0 deletions(-)
gatchat/ppp_net.c +2 -0
index c1f2eb4..fc1f9fb 100644
@@ -50,10 +50,26 @@ struct ppp_net {
 
 void ppp_net_set_mtu(struct ppp_net *net, guint16 mtu)
 {
+	struct ifreq ifr;
+	int sock;

gatchat/ppp_net.c struct ppp_net { · line 64

Quoted 10 lines
gatchat/ppp_net.c +6 -0
+
 	if (net == NULL)
 		return;
 
 	net->mtu = mtu;
+
+	sock = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sock < 0)
+		return;
+

I think it would be a good idea to make this function return a gboolean indicating success or failure instead of silently returning.

gatchat/ppp_net.c struct ppp_net { · line 70

Quoted 6 lines
gatchat/ppp_net.c +6 -0
+	memset(&ifr, 0, sizeof(ifr));
+
+	strncpy(ifr.ifr_name, net->if_name, sizeof(ifr.ifr_name));
+	ifr.ifr_mtu = mtu;
+	if (ioctl(sock, SIOCSIFMTU, (caddr_t) &ifr) < 0)
+		g_printerr("Unable to change MTU\n");

Generally the preferred style is to not have a space after memset but do have space before the if.

gatchat/ppp_net.c struct ppp_net { · line 75

Quoted 6 lines
gatchat/ppp_net.c +2 -0
+
+	close(sock);
 }
 
 void ppp_net_process_packet(struct ppp_net *net, guint8 *packet)

Otherwise patch looks good.

Regards,
-Denis