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SLPD rewrite for IPv6 - IPv4 has been dropped

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After first tests it came out, that RoadWarriors with multiple
active Interfaces hat problems with receiving on/ and sending SLPD
packets to specific interfaces.

Here the solution:
- Define SLPDInterface in your tinc.conf (multiple definitions are allowed)
  On those interfaces tincd will send and receive SLPD packetes
- You have to have IPv6 support on - link-local addresses configured
- tincd must listen on IPv6 on your SLPDInterfaces
- Define SLPDGroup to something like ff02::42:1
- Define SLPDPort for your group
- Define SLPDInterval to some sane number of seconds (0 is default,
meaning SLPD is disabled, 30 seconds should be enough for average
users)

SLPDGroup and SLPDPort should be unique for your network.

Fingerprinting, message signing is yet to be implemented.
Discovered address should also expire periodically.
This commit is contained in:
thorkill 2016-05-16 20:11:08 +02:00
parent 057ccb8da6
commit 43ed440176
5 changed files with 119 additions and 61 deletions
Download patch file Download diff file Expand all files Collapse all files

91
src/net_setup.c
View file

@ -319,7 +319,15 @@ static timeout_t edgeupdate_timeout;
static timeout_t slpdupdate_timeout;
static void slpdupdate_handler(void *data) {
send_slpd_broadcast();
config_t *c_iface;
c_iface = lookup_config(config_tree, "SLPDInterface");
while(c_iface) {
logger(DEBUG_STATUS, LOG_NOTICE, "Sending SLPD out on %s", c_iface->value);
send_slpd_broadcast(c_iface->value);
c_iface = lookup_config_next(config_tree, c_iface);
}
timeout_set(data, &(struct timeval){slpdinterval + (rand() % 10), rand() % 100000});
}
@ -333,50 +341,72 @@ static void edgeupdate_handler(void *data) {
timeout_set(data, &(struct timeval){edgeupdateinterval + (rand() % 10), rand() % 100000});
}
void send_slpd_broadcast(void) {
void send_slpd_broadcast(char *iface) {
int sd;
struct sockaddr_in address;
char slpd_msg[MAXSIZE] = "";
char *iface;
struct in_addr lif;
struct ifreq ifr;
int fd;
struct addrinfo *mcast_addr;
struct addrinfo hints;
sockaddr_t r;
sd = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP);
if (sd < 0) {
char slpd_msg[MAXSIZE] = "";
/* Check if interface is up */
struct ifreq ifr;
sd = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
memset(&ifr, 0, sizeof(ifr));
strcpy(ifr.ifr_name, iface);
if (ioctl(sd, SIOCGIFFLAGS, &ifr) < 0) {
logger(DEBUG_ALWAYS, LOG_INFO, "ioctl() on %s error: [%s:%d]", iface, strerror(errno), errno);
}
close(sd);
// Requested interface is down
if (!(ifr.ifr_flags & IFF_UP) || !(ifr.ifr_flags & IFF_RUNNING))
return;
bzero(&hints, sizeof(hints));
hints.ai_family = AF_INET6;
hints.ai_socktype = SOCK_DGRAM;
hints.ai_flags = AI_ADDRCONFIG | AI_CANONNAME;
int status;
if ((status = getaddrinfo(my_slpd_group, my_slpd_port, &hints, &mcast_addr)) != 0 ) {
logger(DEBUG_ALWAYS, LOG_INFO, "getaddrinfo() error: [%s:%d]", strerror(errno), errno);
return;
}
if ((sd = socket(mcast_addr->ai_family, mcast_addr->ai_socktype, 0)) < 0 ) {
logger(DEBUG_ALWAYS, LOG_INFO, "socket() error: [%s:%d]", strerror(errno), errno);
freeaddrinfo(&mcast_addr);
return;
}
int on = 1;
if (setsockopt(sd, IPPROTO_IPV6, IPV6_V6ONLY, (char *)&on, sizeof(on)) < 0) {
logger(DEBUG_ALWAYS, LOG_ERR, "setsockopt() IPV6_V6ONLY failed [%s:%d]", strerror(errno), errno);
return;
}
/* Send SLPD only on this Interface */
if(get_config_string (lookup_config (config_tree, "SLPDInterface"), &iface)) {
fd = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
ifr.ifr_addr.sa_family = AF_INET;
strncpy(ifr.ifr_name, iface, IFNAMSIZ-1);
ioctl(fd, SIOCGIFADDR, &ifr);
close(fd);
/* display result */
logger(DEBUG_SCARY_THINGS, LOG_ERR, "%s has the ip: %s\n", iface,
inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr));
lif.s_addr = inet_addr(inet_ntoa(((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr));
if(setsockopt(sd, IPPROTO_IP, IP_MULTICAST_IF, (char *)&lif, sizeof(lif)) < 0) {
logger(DEBUG_ALWAYS, LOG_ERR, "can not bind multicast to %s\n", iface);
return;
}
unsigned int ifindex;
ifindex = if_nametoindex(iface);
if(setsockopt (sd, IPPROTO_IPV6, IPV6_MULTICAST_IF, &ifindex, sizeof(ifindex)) != 0) {
logger(DEBUG_ALWAYS, LOG_ERR, "setsockopt() IPV6_MULTICAST_IF failed [%s:%d]", strerror(errno), errno);
freeaddrinfo(&mcast_addr);
return;
}
memset (&address, 0, sizeof (address));
address.sin_family = AF_INET;
address.sin_addr.s_addr = inet_addr (DEFAULT_SLPD_GROUP);
address.sin_port = htons(atoi(my_slpd_port));
unsigned int reuse = 1;
if(setsockopt (sd, IPPROTO_IPV6, SO_REUSEADDR, (char*)&reuse, sizeof(reuse)) != 0) {
logger(DEBUG_ALWAYS, LOG_ERR, "setsockopt() SO_REUSEADDR failed: [%s:%d]", strerror(errno), errno);
freeaddrinfo(&mcast_addr);
return;
}
snprintf(slpd_msg, MAXSIZE, "sLPD 0 1 %s %d none ", myname, atoi(myport));
slpd_msg[MAXSIZE-1] = '\00';
//ecdsa_sign(myself->sptps.mykey, msg, strlen(msg), sig);
if (sendto( sd, slpd_msg, strlen(slpd_msg), 0, (struct sockaddr *) &address, sizeof (address)) < 0) {
if (sendto(sd, slpd_msg, strlen(slpd_msg), 0, mcast_addr->ai_addr, mcast_addr->ai_addrlen) != strlen(slpd_msg) ) {
logger(DEBUG_ALWAYS, LOG_ERR, "SLPD send() error: [%s:%d]", strerror(errno), errno);
}
close(sd);
@ -1136,6 +1166,7 @@ static bool setup_myself(void) {
int slpd_fd = setup_slpd_in_socket();
if (slpd_fd < 0) {
close(slpd_fd);
logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Listening on multicast group failed");
} else {
logger(DEBUG_CONNECTIONS, LOG_NOTICE, "Listening on multicast group");
io_add(&listen_socket[listen_sockets].udp, handle_incoming_slpd_data, &listen_socket[listen_sockets], slpd_fd, IO_READ);