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dns-debug: support record fail packet for debugging

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This commit is contained in:
Nick Peng
2022-07-31 15:49:10 +08:00
parent ab415f2ee9
commit ac042e8bee
10 changed files with 363 additions and 56 deletions
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283
src/util.c
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@@ -34,12 +34,13 @@
#include <openssl/crypto.h>
#include <openssl/ssl.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
@@ -79,6 +80,8 @@
#define NETLINK_ALIGN(len) (((len) + 3) & ~(3))
#define BUFF_SZ 1024
#define PACKET_BUF_SIZE 8192
#define PACKET_MAGIC 0X11040918
struct ipset_netlink_attr {
unsigned short len;
@@ -641,7 +644,7 @@ unsigned char *SSL_SHA256(const unsigned char *d, size_t n, unsigned char *md)
md = m;
}
EVP_MD_CTX* ctx = EVP_MD_CTX_create();
EVP_MD_CTX *ctx = EVP_MD_CTX_create();
if (ctx == NULL) {
return NULL;
}
@@ -1159,7 +1162,7 @@ void bug_ext(const char *file, int line, const char *func, const char *errfmt, .
int write_file(const char *filename, void *data, int data_len)
{
int fd = open(filename, O_WRONLY|O_CREAT, 0644);
int fd = open(filename, O_WRONLY | O_CREAT, 0644);
if (fd < 0) {
return -1;
}
@@ -1178,3 +1181,277 @@ errout:
return -1;
}
int dns_packet_save(const char *dir, const char *type, const char *from, const void *packet, int packet_len)
{
char *data = NULL;
int data_len = 0;
char filename[BUFF_SZ];
char time_s[BUFF_SZ];
int ret = -1;
struct tm *ptm;
struct tm tm;
struct timeval tmval;
struct stat sb;
if (stat(dir, &sb) != 0) {
mkdir(dir, 0750);
}
if (gettimeofday(&tmval, NULL) != 0) {
return -1;
}
ptm = localtime_r(&tmval.tv_sec, &tm);
if (ptm == NULL) {
return -1;
}
ret = snprintf(time_s, sizeof(time_s) - 1, "%.4d-%.2d-%.2d %.2d:%.2d:%.2d.%.3d", ptm->tm_year + 1900,
ptm->tm_mon + 1, ptm->tm_mday, ptm->tm_hour, ptm->tm_min, ptm->tm_sec, (int)(tmval.tv_usec / 1000));
ret = snprintf(filename, sizeof(filename) - 1, "%s/%s-%.4d%.2d%.2d-%.2d%.2d%.2d%.1d.packet", dir, type,
ptm->tm_year + 1900, ptm->tm_mon + 1, ptm->tm_mday, ptm->tm_hour, ptm->tm_min, ptm->tm_sec,
(int)(tmval.tv_usec / 100000));
data = malloc(PACKET_BUF_SIZE);
if (data == NULL) {
return -1;
}
data_len = snprintf(data, PACKET_BUF_SIZE,
"type: %s\n"
"from: %s\n"
"time: %s\n"
"packet-len: %d\n",
type, from, time_s, packet_len);
if (data_len <= 0 || data_len >= PACKET_BUF_SIZE) {
goto out;
}
data[data_len] = 0;
data_len++;
uint32_t magic = htonl(PACKET_MAGIC);
memcpy(data + data_len, &magic, sizeof(magic));
data_len += sizeof(magic);
int len_in_h = htonl(packet_len);
memcpy(data + data_len, &len_in_h, sizeof(len_in_h));
data_len += 4;
memcpy(data + data_len, packet, packet_len);
data_len += packet_len;
ret = write_file(filename, data, data_len);
if (ret != 0) {
goto out;
}
ret = 0;
out:
if (data) {
free(data);
}
return ret;
}
#ifdef DEBUG
struct _dns_read_packet_info {
int data_len;
int message_len;
char *message;
int packet_len;
uint8_t *packet;
uint8_t data[0];
};
static struct _dns_read_packet_info *_dns_read_packet_file(const char *packet_file)
{
struct _dns_read_packet_info *info = NULL;
int fd = 0;
int len = 0;
int message_len = 0;
uint8_t *ptr = NULL;
info = malloc(sizeof(struct _dns_read_packet_info) + PACKET_BUF_SIZE);
fd = open(packet_file, O_RDONLY);
if (fd < 0) {
printf("open file %s failed, %s\n", packet_file, strerror(errno));
goto errout;
}
len = read(fd, info->data, PACKET_BUF_SIZE);
if (len < 0) {
printf("read file %s failed, %s\n", packet_file, strerror(errno));
goto errout;
}
message_len = strnlen((char *)info->data, PACKET_BUF_SIZE);
if (message_len >= 512 || message_len >= len) {
printf("invalid packet file, bad message len\n");
goto errout;
}
info->message_len = message_len;
info->message = (char *)info->data;
ptr = info->data + message_len + 1;
uint32_t magic = 0;
if (ptr - (uint8_t *)info + sizeof(magic) >= (size_t)len) {
printf("invalid packet file, magic length is invalid.\n");
goto errout;
}
memcpy(&magic, ptr, sizeof(magic));
if (magic != htonl(PACKET_MAGIC)) {
printf("invalid packet file, bad magic\n");
goto errout;
}
ptr += sizeof(magic);
uint32_t packet_len = 0;
if (ptr - info->data + sizeof(packet_len) >= (size_t)len) {
printf("invalid packet file, packet length is invalid.\n");
goto errout;
}
memcpy(&packet_len, ptr, sizeof(packet_len));
packet_len = ntohl(packet_len);
ptr += sizeof(packet_len);
if (packet_len != (size_t)len - (ptr - info->data)) {
printf("invalid packet file, packet length is invalid\n");
goto errout;
}
info->packet_len = packet_len;
info->packet = ptr;
close(fd);
return info;
errout:
if (fd > 0) {
close(fd);
}
if (info) {
free(info);
}
return NULL;
}
static int _dns_debug_display(struct dns_packet *packet)
{
int i = 0;
int j = 0;
int ttl = 0;
struct dns_rrs *rrs = NULL;
int rr_count = 0;
char req_host[MAX_IP_LEN];
for (j = 1; j < DNS_RRS_END; j++) {
rrs = dns_get_rrs_start(packet, j, &rr_count);
printf("section: %d\n", j);
for (i = 0; i < rr_count && rrs; i++, rrs = dns_get_rrs_next(packet, rrs)) {
switch (rrs->type) {
case DNS_T_A: {
unsigned char addr[4];
char name[DNS_MAX_CNAME_LEN] = {0};
/* get A result */
dns_get_A(rrs, name, DNS_MAX_CNAME_LEN, &ttl, addr);
req_host[0] = '\0';
inet_ntop(AF_INET, addr, req_host, sizeof(req_host));
printf("domain: %s A: %s TTL: %d\n", name, req_host, ttl);
} break;
case DNS_T_AAAA: {
unsigned char addr[16];
char name[DNS_MAX_CNAME_LEN] = {0};
dns_get_AAAA(rrs, name, DNS_MAX_CNAME_LEN, &ttl, addr);
req_host[0] = '\0';
inet_ntop(AF_INET6, addr, req_host, sizeof(req_host));
printf("domain: %s AAAA: %s TTL:%d\n", name, req_host, ttl);
} break;
case DNS_T_NS: {
char cname[DNS_MAX_CNAME_LEN];
char name[DNS_MAX_CNAME_LEN] = {0};
dns_get_CNAME(rrs, name, DNS_MAX_CNAME_LEN, &ttl, cname, DNS_MAX_CNAME_LEN);
printf("domain: %s TTL: %d NS: %s\n", name, ttl, cname);
} break;
case DNS_T_CNAME: {
char cname[DNS_MAX_CNAME_LEN];
char name[DNS_MAX_CNAME_LEN] = {0};
if (dns_conf_force_no_cname) {
continue;
}
dns_get_CNAME(rrs, name, DNS_MAX_CNAME_LEN, &ttl, cname, DNS_MAX_CNAME_LEN);
printf("domain: %s TTL: %d CNAME: %s\n", name, ttl, cname);
} break;
case DNS_T_SOA: {
char name[DNS_MAX_CNAME_LEN] = {0};
struct dns_soa soa;
dns_get_SOA(rrs, name, 128, &ttl, &soa);
printf("domain: %s SOA: mname: %s, rname: %s, serial: %d, refresh: %d, retry: %d, expire: "
"%d, minimum: %d",
name, soa.mname, soa.rname, soa.serial, soa.refresh, soa.retry, soa.expire, soa.minimum);
} break;
default:
break;
}
}
printf("\n");
}
return 0;
}
int dns_packet_debug(const char *packet_file)
{
struct _dns_read_packet_info *info = NULL;
char buff[DNS_PACKSIZE];
tlog_setlogscreen_only(1);
tlog_setlevel(TLOG_DEBUG);
info = _dns_read_packet_file(packet_file);
if (info == NULL) {
goto errout;
}
const char *send_env = getenv("SMARTDNS_DEBUG_SEND");
if (send_env != NULL) {
char ip[32];
int port = 53;
if (parse_ip(send_env, ip, &port) == 0) {
int sockfd = socket(AF_INET, SOCK_DGRAM, 0);
if (sockfd > 0) {
struct sockaddr_in server;
server.sin_family = AF_INET;
server.sin_port = htons(port);
server.sin_addr.s_addr = inet_addr(ip);
sendto(sockfd, info->packet, info->packet_len, 0, (struct sockaddr *)&server, sizeof(server));
close(sockfd);
}
}
}
struct dns_packet *packet = (struct dns_packet *)buff;
if (dns_decode(packet, DNS_PACKSIZE, info->packet, info->packet_len) != 0) {
printf("decode failed.\n");
goto errout;
}
_dns_debug_display(packet);
free(info);
return 0;
errout:
if (info) {
free(info);
}
return -1;
}
#endif