From: Matt Corallo <git@bluematt.me>
Date: Wed, 16 Mar 2022 04:40:48 +0000 (+0000)
Subject: Auto-configure tun interface
X-Git-Url: http://git.bitcoin.ninja/index.cgi?p=tunudptotcp;a=commitdiff_plain;h=487fcef7148730fec86f39738823689487ad24c3

Auto-configure tun interface
---

diff --git a/main.cpp b/main.cpp
index 09802ce..eff9b46 100644
--- a/main.cpp
+++ b/main.cpp
@@ -29,11 +29,13 @@ int getrandom(void* buf, size_t len, unsigned int flags) {
 }
 #endif
 
+#define PACKET_READ_SIZE 1500
 
-static int tun_alloc(char *dev, int queues, int *fds)
+static int tun_alloc(char *dev, const char* local_ip, const char* remote_ip, int queues, int *fds)
 {
 	struct ifreq ifr;
 	int fd, err, i;
+	char buf[1024];
 
 	if (!dev)
 		return -1;
@@ -58,6 +60,23 @@ static int tun_alloc(char *dev, int queues, int *fds)
 		}
 		fds[i] = fd;
 	}
+
+	sprintf(buf, "ip link set %s mtu %d", dev, PACKET_READ_SIZE);
+	err = system(buf);
+	if (err) goto err;
+
+	sprintf(buf, "ip addr add %s/32 dev %s", local_ip, dev);
+	err = system(buf);
+	if (err) goto err;
+
+	sprintf(buf, "ip link set %s up", dev);
+	err = system(buf);
+	if (err) goto err;
+
+	sprintf(buf, "ip route add %s/32 dev %s", remote_ip, dev);
+	err = system(buf);
+	if (err) goto err;
+
 	return 0;
 err:
 	for (--i; i >= 0; i--)
@@ -585,7 +604,7 @@ int main(int argc, char* argv[]) {
 	// Create tun and bind to sockets...
 	//
 
-	if (tun_alloc(tun_name, TUN_IF_COUNT, fd) != 0) {
+	if (tun_alloc(tun_name, argv[3], argv[2], TUN_IF_COUNT, fd) != 0) {
 		fprintf(stderr, "Failed to alloc tun if\n");
 		return -1;
 	}