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ADD EDNS check feature, TCP server bugfix

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This commit is contained in:
Nick Peng
2018-12-20 00:16:32 +08:00
parent 3d8155e67b
commit 40740f531b
8 changed files with 230 additions and 52 deletions
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175
src/dns.c
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@@ -184,6 +184,9 @@ int dns_rr_add_end(struct dns_packet *packet, int type, dns_type_t rtype, int le
count = &head->nrcount;
start = &packet->additional;
break;
case DNS_RRS_OPT:
count = &packet->optcount;
start = &packet->optional;
default:
return -1;
break;
@@ -638,10 +641,23 @@ int dns_get_SOA(struct dns_rrs *rrs, char *domain, int maxsize, int *ttl, struct
return 0;
}
int dns_set_OPT_payload_size(struct dns_packet *packet, int payload_size)
{
if (payload_size < 512) {
payload_size = 512;
}
packet->payloadsize = payload_size;
return 0;
}
int dns_get_OPT_payload_size(struct dns_packet *packet)
{
return packet->payloadsize;
}
int dns_add_OPT_ECS(struct dns_packet *packet, dns_rr_type type, struct dns_opt_ecs *ecs)
{
// TODO
unsigned char opt_data[DNS_MAX_OPT_LEN];
struct dns_opt *opt = (struct dns_opt *)opt_data;
int len = 0;
@@ -655,18 +671,21 @@ int dns_add_OPT_ECS(struct dns_packet *packet, dns_rr_type type, struct dns_opt_
len += (ecs->source_prefix / 8);
len += (ecs->source_prefix % 8 > 0) ? 1 : 0;
return dns_add_OPT(packet, type, DNS_OPT_T_ECS, len, opt);
return dns_add_RAW(packet, DNS_RRS_OPT, DNS_OPT_T_ECS, "", 0, opt_data, len);
}
int dns_get_OPT_ECS(struct dns_rrs *rrs, unsigned short *opt_code, unsigned short *opt_len, struct dns_opt_ecs *ecs)
{
// TODO
unsigned char opt_data[DNS_MAX_OPT_LEN];
struct dns_opt *opt = (struct dns_opt *)opt_data;
int len = sizeof(opt_data);
int len = DNS_MAX_OPT_LEN;
int ttl = 0;
if (dns_get_OPT(rrs, opt_code, opt_len, opt, &len) != 0) {
if (dns_get_RAW(rrs, 0, 0, &ttl, opt_data, &len) != 0) {
return -1;
}
if (len < sizeof(*opt)) {
return -1;
}
@@ -801,6 +820,20 @@ static int _dns_encode_head(struct dns_context *context)
return len;
}
static int _dns_encode_head_count(struct dns_context *context)
{
int len = 12;
struct dns_head *head = &context->packet->head;
unsigned char *ptr = context->data;
ptr += 4;
dns_write_short(&ptr, head->qdcount);
dns_write_short(&ptr, head->ancount);
dns_write_short(&ptr, head->nscount);
dns_write_short(&ptr, head->nrcount);
return len;
}
static int _dns_decode_domain(struct dns_context *context, char *output, int size)
{
int output_len = 0;
@@ -880,7 +913,6 @@ static int _dns_decode_domain(struct dns_context *context, char *output, int siz
static int _dns_encode_domain(struct dns_context *context, char *domain)
{
int num = 0;
int total_len = 0;
unsigned char *ptr_num = context->ptr++;
/*[len]string[len]string...[0]0 */
@@ -897,15 +929,12 @@ static int _dns_encode_domain(struct dns_context *context, char *domain)
num++;
context->ptr++;
domain++;
total_len++;
}
*ptr_num = num;
if (total_len > 0) {
/* if domain is '\0', [domain] is '\0' */
*(context->ptr) = 0;
context->ptr++;
}
/* if domain is '\0', [domain] is '\0' */
*(context->ptr) = 0;
context->ptr++;
return 0;
}
@@ -1238,8 +1267,97 @@ static int _dns_decode_opt_ecs(struct dns_context *context, struct dns_opt_ecs *
int _dns_encode_OPT(struct dns_context *context, struct dns_rrs *rrs)
{
// TODO
int ret;
int opt_code = 0;
int qclass = 0;
char domain[DNS_MAX_CNAME_LEN];
struct dns_data_context data_context;
int rr_len = 0;
int ttl;
data_context.data = rrs->data;
data_context.ptr = rrs->data;
data_context.maxsize = rrs->len;
ret = _dns_get_rr_head(&data_context, domain, DNS_MAX_CNAME_LEN, &opt_code, &qclass, &ttl, &rr_len);
if (ret < 0) {
return -1;
}
if (_dns_left_len(context) < (4 + rr_len)) {
return -1;
}
dns_write_short(&context->ptr, opt_code);
dns_write_short(&context->ptr, rr_len);
memcpy(context->ptr, data_context.ptr, rr_len);
context->ptr += rr_len;
return 0;
}
int _dns_get_opts_data_len(struct dns_packet *packet, struct dns_rrs *rrs, int count)
{
int i = 0;
int len = 0;
int opt_code = 0;
int qclass = 0;
int ttl;
int ret;
char domain[DNS_MAX_CNAME_LEN];
struct dns_data_context data_context;
int rr_len = 0;
for (i = 0; i < count && rrs; i++, rrs = dns_get_rrs_next(packet, rrs)) {
data_context.data = rrs->data;
data_context.ptr = rrs->data;
data_context.maxsize = rrs->len;
ret = _dns_get_rr_head(&data_context, domain, DNS_MAX_CNAME_LEN, &opt_code, &qclass, &ttl, &rr_len);
if (ret < 0) {
return -1;
}
len += rr_len;
}
return len;
}
int _dns_encode_opts(struct dns_packet *packet, struct dns_context *context, struct dns_rrs *rrs, int count)
{
int i = 0;
int len = 0;
int ret = 0;
unsigned int rcode = 0;
int rr_len = 0;
int payloadsize = packet->payloadsize;
rr_len = _dns_get_opts_data_len(packet, rrs, count);
if (rr_len < 0) {
return -1;
}
if (payloadsize < DNS_DEFAULT_PACKET_SIZE) {
payloadsize = DNS_DEFAULT_PACKET_SIZE;
}
ret = _dns_encode_rr_head(context, "0", DNS_T_OPT, payloadsize, rcode, rr_len);
if (ret < 0) {
return -1;
}
if (_dns_left_len(context) < rr_len) {
return -1;
}
for (i = 0; i < count && rrs; i++, rrs = dns_get_rrs_next(packet, rrs)) {
len = _dns_encode_OPT(context, rrs);
if (len < 0) {
return -1;
}
}
return 0;
}
@@ -1453,6 +1571,8 @@ static int _dns_decode_an(struct dns_context *context, dns_rr_type type)
tlog(TLOG_ERROR, "opt length mitchmatch, %s\n", domain);
return -1;
}
dns_set_OPT_payload_size(packet, qclass);
} break;
default:
context->ptr += rr_len;
@@ -1517,12 +1637,6 @@ static int _dns_encode_an(struct dns_context *context, struct dns_rrs *rrs)
return -1;
}
break;
case DNS_T_OPT:
ret = _dns_encode_OPT(context, rrs);
if (ret < 0) {
return -1;
}
break;
default:
break;
}
@@ -1621,6 +1735,15 @@ static int _dns_encode_body(struct dns_context *context)
}
}
rrs = dns_get_rrs_start(packet, DNS_RRS_OPT, &count);
if (count > 0 || packet->payloadsize > 0) {
len = _dns_encode_opts(packet, context, rrs, count);
if (len < 0) {
return -1;
}
head->nrcount++;
}
return 0;
}
@@ -1641,6 +1764,9 @@ int dns_packet_init(struct dns_packet *packet, int size, struct dns_head *head)
packet->answers = DNS_RR_END;
packet->nameservers = DNS_RR_END;
packet->additional = DNS_RR_END;
packet->optional = DNS_RR_END;
packet->optcount = 0;
packet->payloadsize = 0;
return 0;
}
@@ -1695,6 +1821,11 @@ int dns_encode(unsigned char *data, int size, struct dns_packet *packet)
return -1;
}
ret = _dns_encode_head_count(&context);
if (ret < 0) {
return -1;
}
return context.ptr - context.data;
}