static int handler_udp_tun_to_net(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int dfd, keep = 1;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
struct sockaddr_storage naddr;
socklen_t nlen;
size_t off = sizeof(struct ct_proto) + crypto_box_zerobytes;
if (!buff || len <= off)
return 0;
memset(buff, 0, len);
while ((rlen = read(fd, buff + off, len - off)) > 0) {
dfd = -1; nlen = 0; p = NULL;
memset(&naddr, 0, sizeof(naddr));
hdr = (struct ct_proto *) buff;
memset(hdr, 0, sizeof(*hdr));
hdr->flags = 0;
trie_addr_lookup(buff + off, rlen, ws->parent.ipv4, &dfd, &naddr,
(size_t *) &nlen);
if (unlikely(dfd < 0 || nlen == 0)) {
memset(buff, 0, len);
continue;
}
err = get_user_by_sockaddr(&naddr, nlen, &p);
if (unlikely(err || !p)) {
memset(buff, 0, len);
continue;
}
clen = curve25519_encode(ws->c, p, (unsigned char *) (buff + off -
crypto_box_zerobytes), (rlen +
crypto_box_zerobytes), (unsigned char **)
&cbuff);
if (unlikely(clen <= 0)) {
memset(buff, 0, len);
continue;
}
hdr->payload = htons((uint16_t) clen);
set_udp_cork(dfd);
sendto(dfd, hdr, sizeof(struct ct_proto), 0, (struct sockaddr *)
&naddr, nlen);
sendto(dfd, cbuff, clen, 0, (struct sockaddr *) &naddr, nlen);
set_udp_uncork(dfd);
memset(buff, 0, len);
}
return keep;
}
static int handler_udp_tun_to_net(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int dfd, state, keep = 1;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
struct sockaddr_storage naddr;
socklen_t nlen;
size_t off = sizeof(struct ct_proto) + crypto_box_zerobytes;
if (!buff || len <= off) {
errno = EINVAL;
return 0;
}
errno = 0;
memset(buff, 0, len);
while ((rlen = read(fd, buff + off, len - off)) > 0) {
dfd = -1;
nlen = 0;
p = NULL;
memset(&naddr, 0, sizeof(naddr));
hdr = (struct ct_proto *) buff;
memset(hdr, 0, sizeof(*hdr));
hdr->flags = 0;
trie_addr_lookup(buff + off, rlen, ws->parent.ipv4, &dfd, &naddr,
(size_t *) &nlen);
if (unlikely(dfd < 0 || nlen == 0)) {
syslog(LOG_INFO, "CPU%u: UDP tunnel lookup failed: "
"unknown destination\n", ws->cpu);
memset(buff, 0, len);
continue;
}
err = get_user_by_sockaddr(&naddr, nlen, &p);
if (unlikely(err || !p)) {
syslog(LOG_ERR, "CPU%u: User protocol not in cache! "
"Dropping connection!\n", ws->cpu);
memset(buff, 0, len);
continue;
}
clen = curve25519_encode(ws->c, p, (unsigned char *) (buff + off -
crypto_box_zerobytes), (rlen +
crypto_box_zerobytes), (unsigned char **)
&cbuff);
if (unlikely(clen <= 0)) {
syslog(LOG_ERR, "CPU%u: UDP tunnel encrypt error: %zd\n",
ws->cpu, clen);
memset(buff, 0, len);
continue;
}
hdr->payload = htons((uint16_t) clen);
state = 1;
setsockopt(dfd, IPPROTO_UDP, UDP_CORK, &state, sizeof(state));
err = sendto(dfd, hdr, sizeof(struct ct_proto), 0,
(struct sockaddr *) &naddr, nlen);
if (unlikely(err < 0))
syslog(LOG_ERR, "CPU%u: UDP tunnel write error: %s\n",
ws->cpu, strerror(errno));
err = sendto(dfd, cbuff, clen, 0, (struct sockaddr *) &naddr,
nlen);
if (unlikely(err < 0))
syslog(LOG_ERR, "CPU%u: UDP tunnel write error: %s\n",
ws->cpu, strerror(errno));
state = 0;
setsockopt(dfd, IPPROTO_UDP, UDP_CORK, &state, sizeof(state));
errno = 0;
memset(buff, 0, len);
}
if (unlikely(rlen < 0 && errno != EAGAIN))
syslog(LOG_ERR, "CPU%u: UDP tunnel read error: %s\n",
ws->cpu, strerror(errno));
return keep;
}
static int handler_udp_net_to_tun(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int keep = 1;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
struct sockaddr_storage naddr;
socklen_t nlen = sizeof(naddr);
if (!buff || !len)
return 0;
memset(&naddr, 0, sizeof(naddr));
while ((rlen = recvfrom(fd, buff, len, 0, (struct sockaddr *) &naddr,
&nlen)) > 0) {
p = NULL;
hdr = (struct ct_proto *) buff;
if (unlikely(rlen < sizeof(struct ct_proto)))
goto close;
if (unlikely(rlen - sizeof(*hdr) != ntohs(hdr->payload)))
goto close;
if (unlikely(ntohs(hdr->payload) == 0))
goto close;
if (hdr->flags & PROTO_FLAG_EXIT) {
close:
remove_user_by_sockaddr(&naddr, nlen);
trie_addr_remove_addr(&naddr, nlen);
handler_udp_notify_close(fd, &naddr);
return keep;
}
if (hdr->flags & PROTO_FLAG_INIT) {
syslog_maybe(auth_log, LOG_INFO, "Got initial userhash "
"from remote end!\n");
if (unlikely(rlen - sizeof(*hdr) <
sizeof(struct username_struct)))
goto close;
err = try_register_user_by_sockaddr(ws->c,
buff + sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
&naddr, nlen, auth_log);
if (unlikely(err))
goto close;
goto next;
}
err = get_user_by_sockaddr(&naddr, nlen, &p);
if (unlikely(err || !p))
goto close;
clen = curve25519_decode(ws->c, p, (unsigned char *) buff +
sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
(unsigned char **) &cbuff, NULL);
if (unlikely(clen <= 0))
goto close;
cbuff += crypto_box_zerobytes;
clen -= crypto_box_zerobytes;
err = trie_addr_maybe_update(cbuff, clen, ws->parent.ipv4,
fd, &naddr, nlen);
if (unlikely(err))
goto next;
err = write(ws->parent.tunfd, cbuff, clen);
next:
nlen = sizeof(naddr);
memset(&naddr, 0, sizeof(naddr));
}
return keep;
}
static int handler_udp_net_to_tun(int fd, const struct worker_struct *ws,
char *buff, size_t len)
{
int keep = 1;
char *cbuff;
ssize_t rlen, err, clen;
struct ct_proto *hdr;
struct curve25519_proto *p;
struct sockaddr_storage naddr;
socklen_t nlen = sizeof(naddr);
if (!buff || !len) {
errno = EINVAL;
return 0;
}
memset(&naddr, 0, sizeof(naddr));
errno = 0;
while ((rlen = recvfrom(fd, buff, len, 0, (struct sockaddr *) &naddr,
&nlen)) > 0) {
p = NULL;
hdr = (struct ct_proto *) buff;
if (unlikely(rlen < sizeof(struct ct_proto)))
goto close;
if (unlikely(rlen - sizeof(*hdr) != ntohs(hdr->payload)))
goto close;
if (unlikely(ntohs(hdr->payload) == 0))
goto close;
if (hdr->flags & PROTO_FLAG_EXIT) {
close:
remove_user_by_sockaddr(&naddr, nlen);
trie_addr_remove_addr(&naddr, nlen);
handler_udp_notify_close(fd, &naddr);
return keep;
}
if (hdr->flags & PROTO_FLAG_INIT) {
if (auth_log)
syslog(LOG_INFO, "Got initial userhash from remote end!\n");
if (unlikely(rlen - sizeof(*hdr) <
sizeof(struct username_struct)))
goto close;
err = try_register_user_by_sockaddr(ws->c, buff + sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
&naddr, nlen, auth_log);
if (unlikely(err))
goto close;
goto next;
}
err = get_user_by_sockaddr(&naddr, nlen, &p);
if (unlikely(err || !p)) {
syslog(LOG_ERR, "CPU%u: User protocol not in cache! "
"Dropping connection!\n", ws->cpu);
goto close;
}
clen = curve25519_decode(ws->c, p, (unsigned char *) buff +
sizeof(struct ct_proto),
rlen - sizeof(struct ct_proto),
(unsigned char **) &cbuff, NULL);
if (unlikely(clen <= 0)) {
syslog(LOG_ERR, "CPU%u: UDP net decryption error: %zd\n",
ws->cpu, clen);
goto close;
}
cbuff += crypto_box_zerobytes;
clen -= crypto_box_zerobytes;
err = trie_addr_maybe_update(cbuff, clen, ws->parent.ipv4,
fd, &naddr, nlen);
if (unlikely(err)) {
syslog(LOG_INFO, "CPU%u: Malicious packet dropped "
"from id %d\n", ws->cpu, fd);
goto next;
}
err = write(ws->parent.tunfd, cbuff, clen);
if (unlikely(err < 0))
syslog(LOG_ERR, "CPU%u: UDP net write error: %s\n",
ws->cpu, strerror(errno));
next:
nlen = sizeof(naddr);
memset(&naddr, 0, sizeof(naddr));
errno = 0;
}
if (unlikely(rlen < 0 && errno != EAGAIN))
syslog(LOG_ERR, "CPU%u: UDP net read error: %s\n",
ws->cpu, strerror(errno));
return keep;
}
