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Signed-off-by: Dengfeng Liu <[email protected]>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,237 @@ | ||
| #include <stdio.h> | ||
| #include <stdlib.h> | ||
| #include <string.h> | ||
| #include <unistd.h> | ||
| #include <arpa/inet.h> | ||
| #include <event2/event.h> | ||
| #include <pthread.h> | ||
| #include <netinet/in.h> | ||
| #include <resolv.h> | ||
| #include <arpa/nameser.h> | ||
| #include "dns_forward.h" | ||
| #include "debug.h" | ||
| #include "conf.h" | ||
|
|
||
| struct dns_query { | ||
| int client_fd; | ||
| struct sockaddr_in client_addr; | ||
| socklen_t client_len; | ||
| char buffer[512]; | ||
| int buffer_len; | ||
| struct event *dnsmasq_event; | ||
| }; | ||
|
|
||
| static char * | ||
| strrstr(const char *haystack, const char *needle) | ||
| { | ||
| // Find the last occurrence of the substring needle in the string haystack | ||
| char *result = NULL; | ||
| size_t needle_len = strlen(needle); | ||
| size_t haystack_len = strlen(haystack); | ||
| if (needle_len > haystack_len) { | ||
| return NULL; | ||
| } | ||
|
|
||
| for (size_t i = haystack_len - needle_len; i >= 0; i--) { | ||
| if (strncmp(haystack + i, needle, needle_len) == 0) { | ||
| result = (char *)(haystack + i); | ||
| break; | ||
| } | ||
| } | ||
|
|
||
| return result; | ||
| }; | ||
|
|
||
| static void | ||
| process_dns_response(char *response, int response_len) | ||
| { | ||
| ns_msg handle; | ||
| s_config *config = config_get_config(); | ||
|
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||
|
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| if (ns_initparse((const uint8_t *)response, response_len, &handle) < 0) { | ||
| debug(LOG_WARNING, "ns_initparse: %s", strerror(errno)); | ||
| return; | ||
| } | ||
|
|
||
| int msg_count = ns_msg_count(handle, ns_s_an); | ||
| for (int i = 0; i < msg_count; i++) { | ||
| ns_rr rr; | ||
| if (ns_parserr(&handle, ns_s_an, i, &rr) < 0) { | ||
| debug(LOG_WARNING, "ns_parserr: %s", strerror(errno)); | ||
| continue; | ||
| } | ||
|
|
||
| if (ns_rr_type(rr) == ns_t_a) { | ||
| t_domain_trusted *p = NULL; | ||
| char domain[NS_MAXDNAME] = {0}; | ||
| ns_name_uncompress(ns_msg_base(handle), ns_msg_end(handle), ns_rr_name(rr), domain, sizeof(domain)); | ||
| debug(LOG_DEBUG, "Get dns response domain: %s", domain); | ||
| for (p = config->pan_domains_trusted; p; p = p->next) { | ||
| // reverse match the domain, check if the domain include p->domain | ||
| if (strrstr(domain, p->domain) != NULL) { | ||
| struct in_addr addr; | ||
| char cmd[128] = {0}; | ||
| memcpy(&addr, ns_rr_rdata(rr), sizeof(addr)); | ||
| debug(LOG_DEBUG, "Trusted domain: %s -> %s", domain, inet_ntoa(addr)); | ||
| snprintf(cmd, sizeof(cmd), "nft add element set wifidogx_inner_trust_domains %s", inet_ntoa(addr)); | ||
| system(cmd); | ||
| break; | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| static void | ||
| dnsmasq_read_cb(evutil_socket_t fd, short event, void *arg) | ||
| { | ||
| struct dns_query *query = (struct dns_query *)arg; | ||
| char response[512]; | ||
| int response_len = recv(fd, response, sizeof(response), 0); | ||
|
|
||
| if (response_len > 0) { | ||
| debug(LOG_DEBUG, "Received DNS response from dnsmasq"); | ||
|
|
||
| // Process DNS response for trusted domains | ||
| process_dns_response(response, response_len); | ||
|
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||
| // Send the DNS response back to the client | ||
| sendto(query->client_fd, response, response_len, 0, (struct sockaddr *)&query->client_addr, query->client_len); | ||
| debug(LOG_DEBUG, "Sent DNS response to client"); | ||
| } else { | ||
| perror("recv"); | ||
| } | ||
|
|
||
| // Clean up | ||
| event_free(query->dnsmasq_event); | ||
| close(fd); | ||
| free(query); | ||
| } | ||
|
|
||
| static void | ||
| read_cb(evutil_socket_t fd, short event, void *arg) | ||
| { | ||
| struct event_base *base = (struct event_base *)arg; | ||
| struct sockaddr_in client_addr; | ||
| socklen_t client_len = sizeof(client_addr); | ||
| char buffer[512]; | ||
|
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||
| int recv_len = recvfrom(fd, buffer, sizeof(buffer), 0, (struct sockaddr *)&client_addr, &client_len); | ||
| if (recv_len > 0) { | ||
| debug(LOG_DEBUG, "Received DNS request"); | ||
|
|
||
| // Forward DNS query to dnsmasq | ||
| int dnsmasq_sock = socket(AF_INET, SOCK_DGRAM, 0); | ||
| if (dnsmasq_sock < 0) { | ||
| debug(LOG_ERR, "socket: %s", strerror(errno)); | ||
| return; | ||
| } | ||
|
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||
| struct sockaddr_in dnsmasq_addr; | ||
| memset(&dnsmasq_addr, 0, sizeof(dnsmasq_addr)); | ||
| dnsmasq_addr.sin_family = AF_INET; | ||
| dnsmasq_addr.sin_addr.s_addr = inet_addr("127.0.0.1"); | ||
| dnsmasq_addr.sin_port = htons(LOCAL_DNS_PORT); | ||
|
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||
| if (sendto(dnsmasq_sock, buffer, recv_len, 0, (struct sockaddr *)&dnsmasq_addr, sizeof(dnsmasq_addr)) < 0) { | ||
| debug(LOG_ERR, "sendto: %s", strerror(errno)); | ||
| close(dnsmasq_sock); | ||
| return; | ||
| } | ||
|
|
||
| // Create a new dns_query structure | ||
| struct dns_query *query = (struct dns_query *)malloc(sizeof(struct dns_query)); | ||
| if (!query) { | ||
| debug(LOG_ERR, "malloc: %s", strerror(errno)); | ||
| close(dnsmasq_sock); | ||
| return; | ||
| } | ||
| query->client_fd = fd; | ||
| query->client_addr = client_addr; | ||
| query->client_len = client_len; | ||
| memcpy(query->buffer, buffer, recv_len); | ||
| query->buffer_len = recv_len; | ||
|
|
||
| // Set up an event to listen for dnsmasq's response | ||
| query->dnsmasq_event = event_new(base, dnsmasq_sock, EV_READ | EV_PERSIST, dnsmasq_read_cb, query); | ||
| if (!query->dnsmasq_event) { | ||
| debug(LOG_ERR, "event_new: %s", strerror(errno)); | ||
| free(query); | ||
| close(dnsmasq_sock); | ||
| return; | ||
| } | ||
|
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||
| if (event_add(query->dnsmasq_event, NULL) < 0) { | ||
| debug(LOG_ERR, "event_add: %s", strerror(errno)); | ||
| event_free(query->dnsmasq_event); | ||
| free(query); | ||
| close(dnsmasq_sock); | ||
| return; | ||
| } | ||
| } | ||
| } | ||
|
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||
| void * | ||
| dns_forward_thread(void *arg) { | ||
| int sockfd; | ||
| struct sockaddr_in server_addr; | ||
|
|
||
| // Create UDP socket | ||
| if ((sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0) { | ||
| debug(LOG_ERR, "Failed to create socket"); | ||
| return NULL; | ||
| } | ||
|
|
||
| // Bind to port 5353 | ||
| memset(&server_addr, 0, sizeof(server_addr)); | ||
| server_addr.sin_family = AF_INET; | ||
| server_addr.sin_addr.s_addr = INADDR_ANY; | ||
| server_addr.sin_port = htons(DNS_FORWARD_PORT); | ||
|
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||
| if (bind(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) { | ||
| debug(LOG_ERR, "Failed to bind to port %d", DNS_FORWARD_PORT); | ||
| close(sockfd); | ||
| return NULL; | ||
| } | ||
|
|
||
| // Initialize libevent | ||
| struct event_base *base = event_base_new(); | ||
| if (!base) { | ||
| debug(LOG_ERR, "event_base_new: %s", strerror(errno)); | ||
| close(sockfd); | ||
| return NULL; | ||
| } | ||
|
|
||
| // Create an event to listen for incoming DNS requests | ||
| struct event *dns_event = event_new(base, sockfd, EV_READ | EV_PERSIST, read_cb, base); | ||
| if (!dns_event) { | ||
| debug(LOG_ERR, "event_new: %s", strerror(errno)); | ||
| event_base_free(base); | ||
| close(sockfd); | ||
| return NULL; | ||
| } | ||
|
|
||
| // Add the event to the event base | ||
| if (event_add(dns_event, NULL) < 0) { | ||
| debug(LOG_ERR, "event_add: %s", strerror(errno)); | ||
| event_free(dns_event); | ||
| event_base_free(base); | ||
| close(sockfd); | ||
| return NULL; | ||
| } | ||
|
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| debug(LOG_INFO, "DNS forwarder started on port %d", DNS_FORWARD_PORT); | ||
|
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| // Dispatch events | ||
| event_base_dispatch(base); | ||
|
|
||
| // Clean up | ||
| event_free(dns_event); | ||
| event_base_free(base); | ||
| close(sockfd); | ||
|
|
||
| return NULL; | ||
| } | ||
|
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||
|
|
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,9 @@ | ||
| #ifndef _DNS_FORWARD_H_ | ||
| #define _DNS_FORWARD_H_ | ||
|
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| #define DNS_FORWARD_PORT 15353 | ||
| #define LOCAL_DNS_PORT 53 | ||
|
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||
| void *dns_forward_thread(void *); | ||
|
|
||
| #endif |
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