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|
#include "netio.h"
#include "list.h"
#include "dbutil.h"
#include "session.h"
#include "debug.h"
struct dropbear_progress_connection {
struct addrinfo *res;
struct addrinfo *res_iter;
char *remotehost, *remoteport; /* For error reporting */
connect_callback cb;
void *cb_data;
struct Queue *writequeue; /* A queue of encrypted packets to send with TCP fastopen,
or NULL. */
int sock;
char* errstring;
struct addrinfo *bind_addrinfo;
};
/* Deallocate a progress connection. Removes from the pending list if iter!=NULL.
Does not close sockets */
static void remove_connect(struct dropbear_progress_connection *c, m_list_elem *iter) {
if (c->res) {
freeaddrinfo(c->res);
}
m_free(c->remotehost);
m_free(c->remoteport);
m_free(c->errstring);
if (c->bind_addrinfo) freeaddrinfo(c->bind_addrinfo);
m_free(c);
if (iter) {
list_remove(iter);
}
}
static void cancel_callback(int result, int sock, void* UNUSED(data), const char* UNUSED(errstring)) {
if (result == DROPBEAR_SUCCESS)
{
m_close(sock);
}
}
void cancel_connect(struct dropbear_progress_connection *c) {
c->cb = cancel_callback;
c->cb_data = NULL;
}
static void connect_try_next(struct dropbear_progress_connection *c) {
struct addrinfo *r;
int res = 0;
int fastopen = 0;
#if DROPBEAR_CLIENT_TCP_FAST_OPEN
struct msghdr message;
#endif
for (r = c->res_iter; r; r = r->ai_next)
{
dropbear_assert(c->sock == -1);
c->sock = socket(r->ai_family, r->ai_socktype, r->ai_protocol);
if (c->sock < 0) {
continue;
}
if (c->bind_addrinfo) {
if (bind(c->sock, c->bind_addrinfo->ai_addr, c->bind_addrinfo->ai_addrlen) < 0) {
/* failure */
m_free(c->errstring);
c->errstring = m_strdup(strerror(errno));
close(c->sock);
c->sock = -1;
continue;
}
}
ses.maxfd = MAX(ses.maxfd, c->sock);
set_sock_nodelay(c->sock);
setnonblocking(c->sock);
#if DROPBEAR_CLIENT_TCP_FAST_OPEN
fastopen = (c->writequeue != NULL);
if (fastopen) {
memset(&message, 0x0, sizeof(message));
message.msg_name = r->ai_addr;
message.msg_namelen = r->ai_addrlen;
/* 6 is arbitrary, enough to hold initial packets */
unsigned int iovlen = 6; /* Linux msg_iovlen is a size_t */
struct iovec iov[6];
packet_queue_to_iovec(c->writequeue, iov, &iovlen);
message.msg_iov = iov;
message.msg_iovlen = iovlen;
res = sendmsg(c->sock, &message, MSG_FASTOPEN);
/* Returns EINPROGRESS if FASTOPEN wasn't available */
if (res < 0) {
if (errno != EINPROGRESS) {
m_free(c->errstring);
c->errstring = m_strdup(strerror(errno));
/* Not entirely sure which kind of errors are normal - 2.6.32 seems to
return EPIPE for any (nonblocking?) sendmsg(). just fall back */
TRACE(("sendmsg tcp_fastopen failed, falling back. %s", strerror(errno)));
/* No kernel MSG_FASTOPEN support. Fall back below */
fastopen = 0;
/* Set to NULL to avoid trying again */
c->writequeue = NULL;
}
} else {
packet_queue_consume(c->writequeue, res);
}
}
#endif
/* Normal connect(), used as fallback for TCP fastopen too */
if (!fastopen) {
res = connect(c->sock, r->ai_addr, r->ai_addrlen);
}
if (res < 0 && errno != EINPROGRESS) {
/* failure */
m_free(c->errstring);
c->errstring = m_strdup(strerror(errno));
close(c->sock);
c->sock = -1;
continue;
} else {
/* new connection was successful, wait for it to complete */
break;
}
}
if (r) {
c->res_iter = r->ai_next;
} else {
c->res_iter = NULL;
}
}
/* Connect via TCP to a host. */
struct dropbear_progress_connection *connect_remote(const char* remotehost, const char* remoteport,
connect_callback cb, void* cb_data, char* bind_address)
{
struct dropbear_progress_connection *c = NULL;
int err;
struct addrinfo hints;
c = m_malloc(sizeof(*c));
c->remotehost = m_strdup(remotehost);
c->remoteport = m_strdup(remoteport);
c->sock = -1;
c->cb = cb;
c->cb_data = cb_data;
c->bind_addrinfo = NULL;
list_append(&ses.conn_pending, c);
memset(&hints, 0, sizeof(hints));
hints.ai_socktype = SOCK_STREAM;
hints.ai_family = AF_UNSPEC;
err = getaddrinfo(remotehost, remoteport, &hints, &c->res);
if (err) {
int len;
len = 100 + strlen(gai_strerror(err));
c->errstring = (char*)m_malloc(len);
snprintf(c->errstring, len, "Error resolving '%s' port '%s'. %s",
remotehost, remoteport, gai_strerror(err));
TRACE(("Error resolving: %s", gai_strerror(err)))
} else {
c->res_iter = c->res;
}
if (NULL != bind_address) {
memset(&hints, 0, sizeof(hints));
hints.ai_socktype = SOCK_STREAM;
hints.ai_family = AF_UNSPEC;
err = getaddrinfo(bind_address, NULL, &hints, &c->bind_addrinfo);
if (err) {
int len;
len = 100 + strlen(gai_strerror(err));
c->errstring = (char*)m_malloc(len);
snprintf(c->errstring, len, "Error resolving '%s'. %s",
bind_address, gai_strerror(err));
TRACE(("Error resolving: %s", gai_strerror(err)))
c->res_iter = NULL;
}
}
return c;
}
void remove_connect_pending() {
while (ses.conn_pending.first) {
struct dropbear_progress_connection *c = ses.conn_pending.first->item;
remove_connect(c, ses.conn_pending.first);
}
}
void set_connect_fds(fd_set *writefd) {
m_list_elem *iter;
TRACE(("enter set_connect_fds"))
iter = ses.conn_pending.first;
while (iter) {
m_list_elem *next_iter = iter->next;
struct dropbear_progress_connection *c = iter->item;
/* Set one going */
while (c->res_iter && c->sock < 0) {
connect_try_next(c);
}
if (c->sock >= 0) {
FD_SET(c->sock, writefd);
} else {
/* Final failure */
if (!c->errstring) {
c->errstring = m_strdup("unexpected failure");
}
c->cb(DROPBEAR_FAILURE, -1, c->cb_data, c->errstring);
remove_connect(c, iter);
}
iter = next_iter;
}
}
void handle_connect_fds(const fd_set *writefd) {
m_list_elem *iter;
TRACE(("enter handle_connect_fds"))
for (iter = ses.conn_pending.first; iter; iter = iter->next) {
int val;
socklen_t vallen = sizeof(val);
struct dropbear_progress_connection *c = iter->item;
if (c->sock < 0 || !FD_ISSET(c->sock, writefd)) {
continue;
}
TRACE(("handling %s port %s socket %d", c->remotehost, c->remoteport, c->sock));
if (getsockopt(c->sock, SOL_SOCKET, SO_ERROR, &val, &vallen) != 0) {
TRACE(("handle_connect_fds getsockopt(%d) SO_ERROR failed: %s", c->sock, strerror(errno)))
/* This isn't expected to happen - Unix has surprises though, continue gracefully. */
m_close(c->sock);
c->sock = -1;
} else if (val != 0) {
/* Connect failed */
TRACE(("connect to %s port %s failed.", c->remotehost, c->remoteport))
m_close(c->sock);
c->sock = -1;
m_free(c->errstring);
c->errstring = m_strdup(strerror(val));
} else {
/* New connection has been established */
c->cb(DROPBEAR_SUCCESS, c->sock, c->cb_data, NULL);
remove_connect(c, iter);
TRACE(("leave handle_connect_fds - success"))
/* Must return here - remove_connect() invalidates iter */
return;
}
}
TRACE(("leave handle_connect_fds - end iter"))
}
void connect_set_writequeue(struct dropbear_progress_connection *c, struct Queue *writequeue) {
c->writequeue = writequeue;
}
void packet_queue_to_iovec(const struct Queue *queue, struct iovec *iov, unsigned int *iov_count) {
struct Link *l;
unsigned int i;
int len;
buffer *writebuf;
#ifndef IOV_MAX
#define IOV_MAX UIO_MAXIOV
#endif
*iov_count = MIN(MIN(queue->count, IOV_MAX), *iov_count);
for (l = queue->head, i = 0; i < *iov_count; l = l->link, i++)
{
writebuf = (buffer*)l->item;
len = writebuf->len - 1 - writebuf->pos;
dropbear_assert(len > 0);
TRACE2(("write_packet writev #%d type %d len %d/%d", i, writebuf->data[writebuf->len-1],
len, writebuf->len-1))
iov[i].iov_base = buf_getptr(writebuf, len);
iov[i].iov_len = len;
}
}
void packet_queue_consume(struct Queue *queue, ssize_t written) {
buffer *writebuf;
int len;
while (written > 0) {
writebuf = (buffer*)examine(queue);
len = writebuf->len - 1 - writebuf->pos;
if (len > written) {
/* partial buffer write */
buf_incrpos(writebuf, written);
written = 0;
} else {
written -= len;
dequeue(queue);
buf_free(writebuf);
}
}
}
void set_sock_nodelay(int sock) {
int val;
/* disable nagle */
val = 1;
setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void*)&val, sizeof(val));
}
#if DROPBEAR_SERVER_TCP_FAST_OPEN
void set_listen_fast_open(int sock) {
int qlen = MAX(MAX_UNAUTH_PER_IP, 5);
if (setsockopt(sock, SOL_TCP, TCP_FASTOPEN, &qlen, sizeof(qlen)) != 0) {
TRACE(("set_listen_fast_open failed for socket %d: %s", sock, strerror(errno)))
}
}
#endif
void set_sock_priority(int sock, enum dropbear_prio prio) {
int rc;
#ifdef IPTOS_LOWDELAY
int iptos_val = 0;
#endif
#ifdef HAVE_LINUX_PKT_SCHED_H
int so_prio_val = 0;
#endif
/* Don't log ENOTSOCK errors so that this can harmlessly be called
* on a client '-J' proxy pipe */
/* set the TOS bit for either ipv4 or ipv6 */
#ifdef IPTOS_LOWDELAY
if (prio == DROPBEAR_PRIO_LOWDELAY) {
iptos_val = IPTOS_LOWDELAY;
} else if (prio == DROPBEAR_PRIO_BULK) {
iptos_val = IPTOS_THROUGHPUT;
}
#if defined(IPPROTO_IPV6) && defined(IPV6_TCLASS)
rc = setsockopt(sock, IPPROTO_IPV6, IPV6_TCLASS, (void*)&iptos_val, sizeof(iptos_val));
if (rc < 0 && errno != ENOTSOCK) {
TRACE(("Couldn't set IPV6_TCLASS (%s)", strerror(errno)));
}
#endif
rc = setsockopt(sock, IPPROTO_IP, IP_TOS, (void*)&iptos_val, sizeof(iptos_val));
if (rc < 0 && errno != ENOTSOCK) {
TRACE(("Couldn't set IP_TOS (%s)", strerror(errno)));
}
#endif
#ifdef HAVE_LINUX_PKT_SCHED_H
if (prio == DROPBEAR_PRIO_LOWDELAY) {
so_prio_val = TC_PRIO_INTERACTIVE;
} else if (prio == DROPBEAR_PRIO_BULK) {
so_prio_val = TC_PRIO_BULK;
}
/* linux specific, sets QoS class. see tc-prio(8) */
rc = setsockopt(sock, SOL_SOCKET, SO_PRIORITY, (void*) &so_prio_val, sizeof(so_prio_val));
if (rc < 0 && errno != ENOTSOCK)
dropbear_log(LOG_WARNING, "Couldn't set SO_PRIORITY (%s)",
strerror(errno));
#endif
}
/* from openssh/canohost.c avoid premature-optimization */
int get_sock_port(int sock) {
struct sockaddr_storage from;
socklen_t fromlen;
char strport[NI_MAXSERV];
int r;
/* Get IP address of client. */
fromlen = sizeof(from);
memset(&from, 0, sizeof(from));
if (getsockname(sock, (struct sockaddr *)&from, &fromlen) < 0) {
TRACE(("getsockname failed: %d", errno))
return 0;
}
/* Work around Linux IPv6 weirdness */
if (from.ss_family == AF_INET6)
fromlen = sizeof(struct sockaddr_in6);
/* Non-inet sockets don't have a port number. */
if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
return 0;
/* Return port number. */
if ((r = getnameinfo((struct sockaddr *)&from, fromlen, NULL, 0,
strport, sizeof(strport), NI_NUMERICSERV)) != 0) {
TRACE(("netio.c/get_sock_port/getnameinfo NI_NUMERICSERV failed: %d", r))
}
return atoi(strport);
}
/* Listen on address:port.
* Special cases are address of "" listening on everything,
* and address of NULL listening on localhost only.
* Returns the number of sockets bound on success, or -1 on failure. On
* failure, if errstring wasn't NULL, it'll be a newly malloced error
* string.*/
int dropbear_listen(const char* address, const char* port,
int *socks, unsigned int sockcount, char **errstring, int *maxfd) {
struct addrinfo hints, *res = NULL, *res0 = NULL;
int err;
unsigned int nsock;
struct linger linger;
int val;
int sock;
TRACE(("enter dropbear_listen"))
memset(&hints, 0, sizeof(hints));
hints.ai_family = AF_UNSPEC; /* TODO: let them flag v4 only etc */
hints.ai_socktype = SOCK_STREAM;
/* for calling getaddrinfo:
address == NULL and !AI_PASSIVE: local loopback
address == NULL and AI_PASSIVE: all interfaces
address != NULL: whatever the address says */
if (!address) {
TRACE(("dropbear_listen: local loopback"))
} else {
if (address[0] == '\0') {
TRACE(("dropbear_listen: all interfaces"))
address = NULL;
}
hints.ai_flags = AI_PASSIVE;
}
err = getaddrinfo(address, port, &hints, &res0);
if (err) {
if (errstring != NULL && *errstring == NULL) {
int len;
len = 20 + strlen(gai_strerror(err));
*errstring = (char*)m_malloc(len);
snprintf(*errstring, len, "Error resolving: %s", gai_strerror(err));
}
if (res0) {
freeaddrinfo(res0);
res0 = NULL;
}
TRACE(("leave dropbear_listen: failed resolving"))
return -1;
}
/*
* when listening on server-assigned-port 0
* the assigned ports may differ for address families (v4/v6)
* causing problems for tcpip-forward
* caller can do a get_socket_address to discover assigned-port
* hence, use same port for all address families
*/
u_int16_t *allocated_lport_p = 0;
int allocated_lport = 0;
nsock = 0;
for (res = res0; res != NULL && nsock < sockcount;
res = res->ai_next) {
if (allocated_lport > 0) {
if (AF_INET == res->ai_family) {
allocated_lport_p = &((struct sockaddr_in *)res->ai_addr)->sin_port;
} else if (AF_INET6 == res->ai_family) {
allocated_lport_p = &((struct sockaddr_in6 *)res->ai_addr)->sin6_port;
}
*allocated_lport_p = htons(allocated_lport);
}
/* Get a socket */
socks[nsock] = socket(res->ai_family, res->ai_socktype,
res->ai_protocol);
sock = socks[nsock]; /* For clarity */
if (sock < 0) {
err = errno;
TRACE(("socket() failed"))
continue;
}
/* Various useful socket options */
val = 1;
/* set to reuse, quick timeout */
setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void*) &val, sizeof(val));
linger.l_onoff = 1;
linger.l_linger = 5;
setsockopt(sock, SOL_SOCKET, SO_LINGER, (void*)&linger, sizeof(linger));
#if defined(IPPROTO_IPV6) && defined(IPV6_V6ONLY)
if (res->ai_family == AF_INET6) {
int on = 1;
if (setsockopt(sock, IPPROTO_IPV6, IPV6_V6ONLY,
&on, sizeof(on)) == -1) {
dropbear_log(LOG_WARNING, "Couldn't set IPV6_V6ONLY");
}
}
#endif
set_sock_nodelay(sock);
if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
err = errno;
close(sock);
TRACE(("bind(%s) failed", port))
continue;
}
if (listen(sock, DROPBEAR_LISTEN_BACKLOG) < 0) {
err = errno;
close(sock);
TRACE(("listen() failed"))
continue;
}
if (0 == allocated_lport) {
allocated_lport = get_sock_port(sock);
}
*maxfd = MAX(*maxfd, sock);
nsock++;
}
if (res0) {
freeaddrinfo(res0);
res0 = NULL;
}
if (nsock == 0) {
if (errstring != NULL && *errstring == NULL) {
int len;
len = 20 + strlen(strerror(err));
*errstring = (char*)m_malloc(len);
snprintf(*errstring, len, "Error listening: %s", strerror(err));
}
TRACE(("leave dropbear_listen: failure, %s", strerror(err)))
return -1;
}
TRACE(("leave dropbear_listen: success, %d socks bound", nsock))
return nsock;
}
void get_socket_address(int fd, char **local_host, char **local_port,
char **remote_host, char **remote_port, int host_lookup)
{
struct sockaddr_storage addr;
socklen_t addrlen;
if (local_host || local_port) {
addrlen = sizeof(addr);
if (getsockname(fd, (struct sockaddr*)&addr, &addrlen) < 0) {
dropbear_exit("Failed socket address: %s", strerror(errno));
}
getaddrstring(&addr, local_host, local_port, host_lookup);
}
if (remote_host || remote_port) {
addrlen = sizeof(addr);
if (getpeername(fd, (struct sockaddr*)&addr, &addrlen) < 0) {
dropbear_exit("Failed socket address: %s", strerror(errno));
}
getaddrstring(&addr, remote_host, remote_port, host_lookup);
}
}
/* Return a string representation of the socket address passed. The return
* value is allocated with malloc() */
void getaddrstring(struct sockaddr_storage* addr,
char **ret_host, char **ret_port,
int host_lookup) {
char host[NI_MAXHOST+1], serv[NI_MAXSERV+1];
unsigned int len;
int ret;
int flags = NI_NUMERICSERV | NI_NUMERICHOST;
#ifndef DO_HOST_LOOKUP
host_lookup = 0;
#endif
if (host_lookup) {
flags = NI_NUMERICSERV;
}
len = sizeof(struct sockaddr_storage);
/* Some platforms such as Solaris 8 require that len is the length
* of the specific structure. Some older linux systems (glibc 2.1.3
* such as debian potato) have sockaddr_storage.__ss_family instead
* but we'll ignore them */
#ifdef HAVE_STRUCT_SOCKADDR_STORAGE_SS_FAMILY
if (addr->ss_family == AF_INET) {
len = sizeof(struct sockaddr_in);
}
#ifdef AF_INET6
if (addr->ss_family == AF_INET6) {
len = sizeof(struct sockaddr_in6);
}
#endif
#endif
ret = getnameinfo((struct sockaddr*)addr, len, host, sizeof(host)-1,
serv, sizeof(serv)-1, flags);
if (ret != 0) {
if (host_lookup) {
/* On some systems (Darwin does it) we get EINTR from getnameinfo
* somehow. Eew. So we'll just return the IP, since that doesn't seem
* to exhibit that behaviour. */
getaddrstring(addr, ret_host, ret_port, 0);
return;
} else {
/* if we can't do a numeric lookup, something's gone terribly wrong */
dropbear_exit("Failed lookup: %s", gai_strerror(ret));
}
}
if (ret_host) {
*ret_host = m_strdup(host);
}
if (ret_port) {
*ret_port = m_strdup(serv);
}
}
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