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Disregard route if update is a subnet of tun's address #676

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Disregard route if update is a subnet of tun's address #676

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62 changes: 57 additions & 5 deletions programs/ziti-edge-tunnel/netif_driver/linux/tun.c
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Original file line number Diff line number Diff line change
Expand Up @@ -126,6 +126,36 @@ static void route_updates_done(uv_work_t *wr, int status) {
free(wr);
}

static int ipv6_equal_prefix(const struct in6_addr *addr1, const struct in6_addr *addr2, unsigned int prefixlen)
{
const uint32_t *a1 = addr1->s6_addr32;
const uint32_t *a2 = addr2->s6_addr32;
unsigned int nw = prefixlen / 32;
unsigned int nb = prefixlen % 32;

if (memcmp(a1, a2, 4*nw))
return 0;

return !(nb && ((a1[nw] ^ a2[nw]) & htonl(0xffffffffUL << (32 - nb))));
}

static int tun_check_prefix(netif_handle tun, const char *cidr)
{
ziti_address *ifa = &tun->addr;
ziti_address range;

if (parse_ziti_address_str(&range, cidr) < 0 || range.type != ziti_address_cidr)
return -1;

if (range.addr.cidr.af != ifa->addr.cidr.af)
return -1;

if (range.addr.cidr.bits < ifa->addr.cidr.bits)
return 0;

return ipv6_equal_prefix(&range.addr.cidr.ip, &ifa->addr.cidr.ip, ifa->addr.cidr.bits);
}

static void process_routes_updates(uv_work_t *wr) {
struct rt_process_cmd *cmd = wr->data;

Expand Down Expand Up @@ -153,6 +183,12 @@ static void process_routes_updates(uv_work_t *wr) {
// action == 1: add
unsigned action = (uintptr_t) value;
if (action == i) {
/*
* Ignore update if the prefix is a subnetwork of the tun's network
*/
if (tun_check_prefix(cmd->tun, prefix) > 0)
continue;

int len = snprintf(buf, sizeof(buf), "route %s %s dev %s\n", verb, prefix, cmd->tun->name);
if (len < 0 || (size_t) len >= sizeof buf) {
if (len > 0) errno = ENOMEM;
Expand Down Expand Up @@ -450,16 +486,32 @@ netif_driver tun_open(uv_loop_t *loop, uint32_t tun_ip, uint32_t dns_ip, const c
driver->exclude_rt = tun_exclude_rt;
driver->commit_routes = tun_commit_routes;

ziti_address range;
unsigned int prefixlen;
if (!dns_block ||
parse_ziti_address_str(&range, dns_block) < 0 ||
range.type != ziti_address_cidr ||
range.addr.cidr.bits > 32) {
prefixlen = 32;
} else {
prefixlen = range.addr.cidr.bits;
}
tun->addr = (ziti_address) {
.type = ziti_address_cidr,
.addr.cidr.af = AF_INET,
.addr.cidr.bits = prefixlen,
.addr.cidr.ip = { .s6_addr32 = { tun_ip } }
};

run_command("ip link set %s up", tun->name);
run_command("ip addr add %s dev %s", inet_ntoa(*(struct in_addr*)&tun_ip), tun->name);
run_command("ip addr add %s/%d dev %s",
inet_ntoa((struct in_addr){ .s_addr = tun->addr.addr.cidr.ip.s6_addr32[0] }),
tun->addr.addr.cidr.bits,
tun->name);

if (dns_ip) {
init_dns_maintainer(loop, tun->name, dns_ip);
}

if (dns_block) {
run_command("ip route add %s dev %s", dns_block, tun->name);
}

return driver;
}
1 change: 1 addition & 0 deletions programs/ziti-edge-tunnel/netif_driver/linux/tun.h
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
struct netif_handle_s {
int fd;
char name[IFNAMSIZ];
ziti_address addr;

model_map *route_updates;
};
Expand Down