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allow to set and query multiple upstream nameservers #953

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Aug 27, 2024
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allow to set and query multiple upstream nameservers #953

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2 changes: 1 addition & 1 deletion CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.21)


set(ZITI_SDK_DIR "" CACHE FILEPATH "developer option: use local ziti-sdk-c checkout")
set(ZITI_SDK_VERSION "2.0.0-alpha17" CACHE STRING "ziti-sdk-c version or branch to use")
set(ZITI_SDK_VERSION "2.0.0-alpha18" CACHE STRING "ziti-sdk-c version or branch to use")

# if TUNNEL_SDK_ONLY then don't descend into programs/ziti-edge-tunnel
option(TUNNEL_SDK_ONLY "build only ziti-tunnel-sdk (without ziti)" OFF)
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4 changes: 3 additions & 1 deletion lib/ziti-tunnel-cbs/include/ziti/ziti_dns.h
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Expand Up @@ -19,6 +19,8 @@

#include <ziti/ziti_tunnel.h>

#include "ziti_tunnel_cbs.h"

#define DNS_NO_ERROR 0
#define DNS_FORMERR 1
#define DNS_SERVFAIL 2
Expand All @@ -33,7 +35,7 @@ extern "C" {

int ziti_dns_setup(tunneler_context tnlr, const char *dns_addr, const char *dns_cidr);

int ziti_dns_set_upstream(uv_loop_t *l, const char *host, uint16_t port);
int ziti_dns_set_upstream(uv_loop_t *l, tunnel_upstream_dns_array upstreams);

const ip_addr_t *ziti_dns_register_hostname(const ziti_address *addr, void *intercept);

Expand Down
98 changes: 57 additions & 41 deletions lib/ziti-tunnel-cbs/ziti_dns.c
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Expand Up @@ -20,6 +20,7 @@
#include "ziti_instance.h"
#include "dns_host.h"

#define MAX_UPSTREAMS 5
#define MAX_DNS_NAME 256
#define MAX_IP_LENGTH 16

Expand Down Expand Up @@ -63,7 +64,7 @@ static void* on_dns_client(const void *app_intercept_ctx, io_ctx_t *io);
static int on_dns_close(void *dns_io_ctx);
static ssize_t on_dns_req(const void *ziti_io_ctx, void *write_ctx, const void *q_packet, size_t len);
static int query_upstream(struct dns_req *req);
static void udp_alloc(uv_handle_t *h, size_t reqlen, uv_buf_t *b);
static void dns_upstream_alloc(uv_handle_t *h, size_t reqlen, uv_buf_t *b);
static void on_upstream_packet(uv_udp_t *h, ssize_t rc, const uv_buf_t *buf, const struct sockaddr* addr, unsigned int flags);
static void complete_dns_req(struct dns_req *req);
static void free_dns_req(struct dns_req *req);
Expand Down Expand Up @@ -112,7 +113,8 @@ struct ziti_dns_s {
model_map requests;
uv_udp_t upstream;
bool is_ipv4;
struct sockaddr_in6 upstream_addr;
int num_dns_up;
struct sockaddr_in6 upstream_addr[MAX_UPSTREAMS];
} ziti_dns;

static uint32_t next_ipv4() {
Expand Down Expand Up @@ -205,7 +207,7 @@ ZITI_LOG(ERROR, "failed [" #op "]: %d(%s)", rc, uv_strerror(rc)); \
return rc;} \
}while(0)

int ziti_dns_set_upstream(uv_loop_t *l, const char *host, uint16_t port) {
int ziti_dns_set_upstream(uv_loop_t *l, tunnel_upstream_dns_array upstreams) {
if (!uv_is_active((const uv_handle_t *) &ziti_dns.upstream)) {
CHECK_UV(uv_udp_init(l, &ziti_dns.upstream));
int r = uv_udp_bind(&ziti_dns.upstream,
Expand All @@ -226,48 +228,57 @@ int ziti_dns_set_upstream(uv_loop_t *l, const char *host, uint16_t port) {
}
ziti_dns.is_ipv4 = true;
}
CHECK_UV(uv_udp_recv_start(&ziti_dns.upstream, udp_alloc, on_upstream_packet));
CHECK_UV(uv_udp_recv_start(&ziti_dns.upstream, dns_upstream_alloc, on_upstream_packet));
uv_unref((uv_handle_t *) &ziti_dns.upstream);
}

if (port == 0) port = 53;

union {
struct in_addr addr;
uint8_t a[4];
} ipv4;
if (ziti_dns.is_ipv4) {
if (uv_inet_pton(AF_INET, host, &ipv4) == 0) {
((struct sockaddr_in*)&ziti_dns.upstream_addr)->sin_family = AF_INET;
((struct sockaddr_in*)&ziti_dns.upstream_addr)->sin_addr = ipv4.addr;
((struct sockaddr_in*)&ziti_dns.upstream_addr)->sin_port = htons(port);
} else {
ZITI_LOG(WARN, "cannot set non-IPv4 upstream on IPv4 only socket");
}
} else {
// set IPv6 upstream address, mapping IPv4 target to IPv6 space (if needed)
ziti_dns.upstream_addr.sin6_family = AF_INET6;
ziti_dns.upstream_addr.sin6_port = htons(port);
if (uv_inet_pton(AF_INET6, host, &ziti_dns.upstream_addr.sin6_addr) != 0) {
if (uv_inet_pton(AF_INET, host, &ipv4) == 0) {
ziti_dns.upstream_addr.sin6_addr = (struct in6_addr) IN6ADDR_V4MAPPED(ipv4.a);

int idx = 0;
for (int i = 0; upstreams[i] != NULL && idx < MAX_UPSTREAMS; i++) {
const tunnel_upstream_dns *dns = upstreams[i];
int port = dns->port != 0 ? (int)dns->port : 53;

if (ziti_dns.is_ipv4) {
if (uv_inet_pton(AF_INET, dns->host, &ipv4) == 0) {
((struct sockaddr_in *) &ziti_dns.upstream_addr[idx])->sin_family = AF_INET;
((struct sockaddr_in *) &ziti_dns.upstream_addr[idx])->sin_addr = ipv4.addr;
((struct sockaddr_in *) &ziti_dns.upstream_addr[idx])->sin_port = htons(port);
idx++;
} else {
ZITI_LOG(WARN, "upstream address[%s] is not IP format", host);
char port_str[6];
snprintf(port_str, sizeof(port_str), "%hu", port);
uv_getaddrinfo_t req = {0};
CHECK_UV(uv_getaddrinfo(l, &req, NULL, host, port_str, NULL));
memcpy(&ziti_dns.upstream_addr, req.addrinfo->ai_addr, sizeof(ziti_dns.upstream_addr));
ZITI_LOG(WARN, "cannot set non-IPv4 upstream on IPv4 only socket");
}
} else {
// set IPv6 upstream address, mapping IPv4 target to IPv6 space (if needed)
ziti_dns.upstream_addr[idx].sin6_family = AF_INET6;
ziti_dns.upstream_addr[idx].sin6_port = htons(port);
if (uv_inet_pton(AF_INET6, dns->host, &ziti_dns.upstream_addr[idx].sin6_addr) != 0) {
if (uv_inet_pton(AF_INET, dns->host, &ipv4) == 0) {
ziti_dns.upstream_addr[idx].sin6_addr = (struct in6_addr) IN6ADDR_V4MAPPED(ipv4.a);
} else {
ZITI_LOG(WARN, "upstream address[%s] is not IP format", dns->host);
char port_str[6];
snprintf(port_str, sizeof(port_str), "%hu", port);
uv_getaddrinfo_t req = {0};
if(uv_getaddrinfo(l, &req, NULL, dns->host, port_str, NULL) == 0) {
memcpy(&ziti_dns.upstream_addr[idx], req.addrinfo->ai_addr, req.addrinfo->ai_addrlen);
}
}
}
idx++;
}
ZITI_LOG(INFO, "DNS upstream[%d] is set to %s:%hu", idx, dns->host, port);
}
ZITI_LOG(INFO, "DNS upstream is set to %s:%hu", host, port);
ziti_dns.num_dns_up = idx;
return 0;
}


void* on_dns_client(const void *app_intercept_ctx, io_ctx_t *io) {
ZITI_LOG(DEBUG, "new DNS client");
ZITI_LOG(TRACE, "new DNS client");
ziti_dns_client_t *clt = calloc(1, sizeof(ziti_dns_client_t));
io->ziti_io = clt;
clt->io_ctx = io;
Expand Down Expand Up @@ -828,29 +839,35 @@ ssize_t on_dns_req(const void *ziti_io_ctx, void *write_ctx, const void *q_packe

int query_upstream(struct dns_req *req) {
bool avail = uv_is_active((const uv_handle_t *) &ziti_dns.upstream);
bool success = false;
if (avail && req->msg.recursive) {
uv_buf_t buf = uv_buf_init((char *) req->req, req->req_len);
int rc = uv_udp_try_send(&ziti_dns.upstream, &buf, 1, (struct sockaddr*)&ziti_dns.upstream_addr);
if (rc > 0) {
return DNS_NO_ERROR;

for (int i = 0; i < ziti_dns.num_dns_up; i++) {
int rc = uv_udp_try_send(&ziti_dns.upstream, &buf, 1,
(struct sockaddr *) &ziti_dns.upstream_addr[i]);
if (rc > 0) {
success = true;
} else {
ZITI_LOG(WARN, "failed to query[%04x] upstream DNS server[%d]: %d(%s)",
req->id, i, rc, uv_strerror(rc));
}
}
ZITI_LOG(WARN, "failed to query[%04x] upstream DNS server: %d(%s)", req->id, rc, uv_strerror(rc));
}
return DNS_REFUSE;
return success ? DNS_NO_ERROR : DNS_REFUSE;
}

static void udp_alloc(uv_handle_t *h, size_t reqlen, uv_buf_t *b) {
b->base = malloc(1024);
b->len = 1024;
static void dns_upstream_alloc(uv_handle_t *h, size_t reqlen, uv_buf_t *b) {
static char dns_buf[1024];
b->base = dns_buf;
b->len = sizeof(dns_buf);
}

static void on_upstream_packet(uv_udp_t *h, ssize_t rc, const uv_buf_t *buf, const struct sockaddr* addr, unsigned int flags) {
if (rc > 0) {
uint16_t id = DNS_ID(buf->base);
struct dns_req *req = model_map_get_key(&ziti_dns.requests, &id, sizeof(id));
if (req == NULL) {
ZITI_LOG(WARN, "got response for unknown query[%04x] (rc=%zd)", id, rc);
} else {
if (req != NULL) {
ZITI_LOG(TRACE, "upstream sent response to query[%04x] (rc=%zd)", id, rc);
if (rc <= sizeof(req->resp)) {
req->resp_len = rc;
Expand All @@ -861,7 +878,6 @@ static void on_upstream_packet(uv_udp_t *h, ssize_t rc, const uv_buf_t *buf, con
complete_dns_req(req);
}
}
free(buf->base);
}

static void free_dns_req(struct dns_req *req) {
Expand Down
8 changes: 4 additions & 4 deletions lib/ziti-tunnel-cbs/ziti_tunnel_ctrl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -667,19 +667,19 @@ static int process_cmd(const tunnel_command *cmd, command_cb cb, void *ctx) {
}

case TunnelCommand_SetUpstreamDNS: {
tunnel_upstream_dns dns = {};
tunnel_upstream_dns_array upstreams = NULL;
int rc;
if (parse_tunnel_upstream_dns(&dns, cmd->data, strlen(cmd->data)) < 0) {
if (parse_tunnel_upstream_dns_array(&upstreams, cmd->data, strlen(cmd->data)) < 0) {
result.error = "invalid command";
result.success = false;
} else if ((rc = ziti_dns_set_upstream(CMD_CTX.loop, dns.host, dns.port)) != 0) {
} else if ((rc = ziti_dns_set_upstream(CMD_CTX.loop,upstreams)) != 0) {
result.error = (char*)uv_strerror(rc);
result.success = false;
} else {
result.success = true;
result.code = IPC_SUCCESS;
}
free_tunnel_upstream_dns(&dns);
free_tunnel_upstream_dns_array(&upstreams);
break;
}

Expand Down
6 changes: 5 additions & 1 deletion programs/ziti-edge-tunnel/ziti-edge-tunnel.c
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Expand Up @@ -1579,7 +1579,11 @@ static int run_tunnel(uv_loop_t *ziti_loop, uint32_t tun_ip, uint32_t dns_ip, co
ip_addr_t dns_ip4 = IPADDR4_INIT(dns_ip);
ziti_dns_setup(tunneler, ipaddr_ntoa(&dns_ip4), ip_range);
if (dns_upstream) {
ziti_dns_set_upstream(ziti_loop, dns_upstream, 0);
tunnel_upstream_dns upstream = {
.host = dns_upstream
};
tunnel_upstream_dns *a[] = { &upstream, NULL};
ziti_dns_set_upstream(ziti_loop, a);
}
run_tunneler_loop(ziti_loop);
if (tun->close) {
Expand Down
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