Remove addresses from old tun device when stealing leases

src/ip-lease.c

@@ -105,6 +105,8 @@ struct ip_lease_st t;
 
 void steal_ip_leases(struct proc_st* proc, struct proc_st *thief)
 {
+	reset_tun(proc);
+
 	thief->ipv4 = talloc_move(thief, &proc->ipv4);
 	thief->ipv6 = talloc_move(thief, &proc->ipv6);
 }

src/main.h

@@ -245,6 +245,7 @@ void  mslog_hex(const main_server_st * s, const struct proc_st* proc,
 
 int open_tun(main_server_st* s, struct proc_st* proc);
 void close_tun(main_server_st* s, struct proc_st* proc);
+void reset_tun(struct proc_st* proc);
 int set_tun_mtu(main_server_st* s, struct proc_st * proc, unsigned mtu);
 
 int send_cookie_auth_reply(main_server_st* s, struct proc_st* proc,

src/tun.c

@@ -547,6 +547,52 @@ void close_tun(main_server_st * s, struct proc_st *proc)
 	return;
 }
 
+void reset_tun(struct proc_st* proc)
+{
+	if (proc->tun_lease.name[0] != 0) {
+#ifdef SIOCDIFADDR
+		if (proc->ipv4 && proc->ipv4->lip_len > 0) {
+			int fd = socket(AF_INET, SOCK_DGRAM, 0);
+
+			if (fd >= 0) {
+				struct ifreq ifr;
+
+				memset(&ifr, 0, sizeof(ifr));
+				strlcpy(ifr.ifr_name, proc->tun_lease.name, IFNAMSIZ);
+
+				memcpy(&ifr.ifr_addr, &proc->ipv4->lip, proc->ipv4->lip_len);
+				ifr.ifr_addr.sa_len = sizeof(struct sockaddr_in);
+				ifr.ifr_addr.sa_family = AF_INET;
+
+				ioctl(fd, SIOCDIFADDR, &ifr);
+				close(fd);
+			}
+		}
+#endif
+
+#ifdef SIOCDIFADDR_IN6
+		if (proc->ipv6 && proc->ipv6->lip_len > 0) {
+			int fd = socket(AF_INET6, SOCK_DGRAM, 0);
+
+			if (fd >= 0) {
+				struct in6_ifreq ifr6;
+
+				memset(&ifr6, 0, sizeof(ifr6));
+				strlcpy(ifr6.ifr_name, proc->tun_lease.name, IFNAMSIZ);
+
+				memcpy(&ifr6.ifr_addr.sin6_addr, SA_IN6_P(&proc->ipv6->lip),
+					SA_IN_SIZE(proc->ipv6->lip_len));
+				ifr6.ifr_addr.sin6_len = sizeof(struct sockaddr_in6);
+				ifr6.ifr_addr.sin6_family = AF_INET6;
+
+				ioctl(fd, SIOCDIFADDR_IN6, &ifr6);
+				close(fd);
+			}
+		}
+#endif
+	}
+}
+
 #if defined(__OpenBSD__) || defined(TUNSIFHEAD)
 # define TUN_AF_PREFIX 1
 #endif