#include <libubox/uloop.h>
#include <libubox/usock.h>
+#include <libubox/utils.h>
#include "announce.h"
#include "util.h"
#include "dns.h"
-char *rdata_buffer;
-static char *name_buffer;
+char rdata_buffer[MAX_DATA_LEN + 1];
+static char name_buffer[MAX_NAME_LEN + 1];
const char*
dns_type_string(uint16_t type)
return "N/A";
}
-void
-dns_send_question(struct uloop_fd *u, char *question, int type)
+static int
+dns_send_packet(int fd, struct iovec *iov, int iov_len)
{
- unsigned char buffer[MAX_NAME_LEN];
- struct dns_header h = { 0 };
- struct dns_question q = { 0 };
- struct msghdr m = { 0 };
- struct iovec iov[3] = { {0}, {0}, {0} };
- struct sockaddr_in a = { 0 };
- int len;
+ static size_t cmsg_data[( CMSG_SPACE(sizeof(struct in_pktinfo)) / sizeof(size_t)) + 1];
+ static struct sockaddr_in a = {
+ .sin_family = AF_INET,
+ .sin_port = htons(MCAST_PORT),
+ };
+ static struct msghdr m = {
+ .msg_name = (struct sockaddr *) &a,
+ .msg_namelen = sizeof(a),
+ .msg_control = cmsg_data,
+ .msg_controllen = CMSG_LEN(sizeof(struct in_pktinfo)),
+ };
+ struct in_pktinfo *pkti;
+ struct cmsghdr *cmsg;
+
+ m.msg_iov = iov;
+ m.msg_iovlen = iov_len;
+
+ memset(cmsg_data, 0, sizeof(cmsg_data));
+ cmsg = CMSG_FIRSTHDR(&m);
+ cmsg->cmsg_len = m.msg_controllen;
+ cmsg->cmsg_level = IPPROTO_IP;
+ cmsg->cmsg_type = IP_PKTINFO;
+
+ pkti = (struct in_pktinfo*) CMSG_DATA(cmsg);
+ pkti->ipi_ifindex = iface_index;
- a.sin_family = AF_INET;
a.sin_addr.s_addr = inet_addr(MCAST_ADDR);
- a.sin_port = htons(MCAST_PORT);
- h.questions = __cpu_to_be16(1);
+ return sendmsg(fd, &m, 0);
+}
+
+void
+dns_send_question(struct uloop_fd *u, const char *question, int type)
+{
+ static struct dns_header h = {
+ .questions = cpu_to_be16(1),
+ };
+ static struct dns_question q = {
+ .class = cpu_to_be16(1),
+ };
+ static struct iovec iov[] = {
+ {
+ .iov_base = &h,
+ .iov_len = sizeof(h),
+ },
+ {
+ .iov_base = name_buffer,
+ },
+ {
+ .iov_base = &q,
+ .iov_len = sizeof(q),
+ }
+ };
+ int len;
+
q.type = __cpu_to_be16(type);
- q.class = __cpu_to_be16(1);
- len = dn_comp(question, buffer, MAX_NAME_LEN, NULL, NULL);
+ len = dn_comp(question, (void *) name_buffer, sizeof(name_buffer), NULL, NULL);
if (len < 1)
return;
- m.msg_name = &a;
- m.msg_namelen = sizeof(struct sockaddr_in);
- m.msg_iov = iov;
- m.msg_iovlen = 3;
-
- iov[0].iov_base = &h;
- iov[0].iov_len = sizeof(struct dns_header);
-
- iov[1].iov_base = buffer;
iov[1].iov_len = len;
- iov[2].iov_base = &q;
- iov[2].iov_len = sizeof(struct dns_question);
-
- if (sendmsg(u->fd, &m, 0) < 0)
+ if (dns_send_packet(u->fd, iov, ARRAY_SIZE(iov)) < 0)
fprintf(stderr, "failed to send question\n");
else
DBG(1, "Q <- %s %s\n", dns_type_string(type), question);
}
void
-dns_add_answer(int type, uint8_t *rdata, uint16_t rdlength)
+dns_add_answer(int type, const uint8_t *rdata, uint16_t rdlength)
{
struct dns_reply *a = &dns_reply[dns_answer_cnt];
if (dns_answer_cnt == MAX_ANSWER)
}
void
-dns_send_answer(struct uloop_fd *u, char *answer)
+dns_send_answer(struct uloop_fd *u, const char *answer)
{
uint8_t buffer[256];
struct dns_header h = { 0 };
- struct msghdr m = { 0 };
struct iovec *iov;
- struct sockaddr_in in = { 0 };
int len, i;
if (!dns_answer_cnt)
return;
- in.sin_family = AF_INET;
- in.sin_addr.s_addr = inet_addr(MCAST_ADDR);
- in.sin_port = htons(MCAST_PORT);
-
h.answers = __cpu_to_be16(dns_answer_cnt);
h.flags = __cpu_to_be16(0x8400);
- iov = malloc(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1));
- if (!iov)
- return;
-
- m.msg_name = ∈
- m.msg_namelen = sizeof(struct sockaddr_in);
- m.msg_iov = iov;
- m.msg_iovlen = (dns_answer_cnt * 3) + 1;
-
+ iov = alloca(sizeof(struct iovec) * ((dns_answer_cnt * 3) + 1));
iov[0].iov_base = &h;
iov[0].iov_len = sizeof(struct dns_header);
DBG(1, "A <- %s %s\n", dns_type_string(dns_reply[i].type), answer);
}
- if (sendmsg(u->fd, &m, 0) < 0)
+ if (dns_send_packet(u->fd, iov, (dns_answer_cnt * 3) + 1) < 0)
fprintf(stderr, "failed to send question\n");
for (i = 0; i < dns_answer_cnt; i++) {
}
static int
-scan_name(uint8_t *buffer, int len)
+scan_name(const uint8_t *buffer, int len)
{
int offset = 0;
}
char*
-dns_consume_name(uint8_t *base, int blen, uint8_t **data, int *len)
+dns_consume_name(const uint8_t *base, int blen, uint8_t **data, int *len)
{
int nlen = scan_name(*data, *len);
return name_buffer;
}
-
-int
-dns_init(void)
-{
- name_buffer = malloc(MAX_NAME_LEN + 1);
- rdata_buffer = malloc(MAX_DATA_LEN + 1);
-
- if (!name_buffer || !rdata_buffer)
- return -1;
-
- memset(name_buffer, 0, MAX_NAME_LEN + 1);
- memset(rdata_buffer, 0, MAX_NAME_LEN + 1);
-
- return 0;
-}
-
-void
-dns_cleanup(void)
-{
- free(name_buffer);
- free(rdata_buffer);
-}