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SSH port forwarding is now configurable in mid-session. After doing

Browse Source 
Change Settings, the port forwarding setup function is run again,
and tags all existing port forwardings as `do not keep'. Then it
iterates through the config in the normal way; when it encounters a
port forwarding which is already in the tree, it tags it `keep'
rather than setting it up from scratch. Finally, it goes through the
tree and removes any that haven't been labelled `keep'. Hence,
editing the list of forwardings in Change Settings has the effect of
cancelling any forwardings you remove, and adding any new ones.

The SSH panel now appears in the reconfig box, and is empty apart
from a message explaining that it has to be there for subpanels of
it to exist. Better wording for this message would be welcome.

[originally from svn r5030]
This commit is contained in:
Simon Tatham
2004-12-28 14:07:05 +00:00
parent 67f93aa30e
commit 81df0d4253
5 changed files with 375 additions and 158 deletions
Download Patch File Download Diff File Expand all files Collapse all files

195
ssh.c
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@ -497,11 +497,34 @@ struct ssh_channel {
* Hence, in SSH 1 this structure is indexed by destination
* host:port pair, whereas in SSH 2 it is indexed by source port.
*/
struct ssh_portfwd; /* forward declaration */
struct ssh_rportfwd {
unsigned sport, dport;
char dhost[256];
char *sportdesc;
struct ssh_portfwd *pfrec;
};
#define free_rportfwd(pf) ( \
((pf) ? (sfree((pf)->sportdesc)) : (void)0 ), sfree(pf) )
/*
* Separately to the rportfwd tree (which is for looking up port
* open requests from the server), a tree of _these_ structures is
* used to keep track of all the currently open port forwardings,
* so that we can reconfigure in mid-session if the user requests
* it.
*/
struct ssh_portfwd {
int keep;
int type;
unsigned sport, dport;
char *saddr, *daddr;
struct ssh_rportfwd *remote;
void *local;
};
#define free_portfwd(pf) ( \
((pf) ? (sfree((pf)->saddr), sfree((pf)->daddr)) : (void)0 ), sfree(pf) )
struct Packet {
long length;
@ -616,7 +639,7 @@ struct ssh_tag {
struct ssh_channel *mainchan; /* primary session channel */
int exitcode;
tree234 *rportfwds;
tree234 *rportfwds, *portfwds;
enum {
SSH_STATE_PREPACKET,
@ -816,6 +839,47 @@ static int ssh_rportcmp_ssh2(void *av, void *bv)
return 0;
}
/*
* Special form of strcmp which can cope with NULL inputs. NULL is
* defined to sort before even the empty string.
*/
static int nullstrcmp(const char *a, const char *b)
{
if (a == NULL && b == NULL)
return 0;
if (a == NULL)
return -1;
if (b == NULL)
return +1;
return strcmp(a, b);
}
static int ssh_portcmp(void *av, void *bv)
{
struct ssh_portfwd *a = (struct ssh_portfwd *) av;
struct ssh_portfwd *b = (struct ssh_portfwd *) bv;
int i;
if (a->type > b->type)
return +1;
if (a->type < b->type)
return -1;
if ( (i = nullstrcmp(a->saddr, b->saddr)) != 0)
return i < 0 ? -1 : +1;
if (a->sport > b->sport)
return +1;
if (a->sport < b->sport)
return -1;
if (a->type != 'D') {
if ( (i = nullstrcmp(a->daddr, b->daddr)) != 0)
return i < 0 ? -1 : +1;
if (a->dport > b->dport)
return +1;
if (a->dport < b->dport)
return -1;
}
return 0;
}
static int alloc_channel_id(Ssh ssh)
{
const unsigned CHANNEL_NUMBER_OFFSET = 256;
@ -3596,8 +3660,7 @@ static void ssh_rportfwd_succfail(Ssh ssh, struct Packet *pktin, void *ctx)
rpf = del234(ssh->rportfwds, pf);
assert(rpf == pf);
sfree(pf->sportdesc);
sfree(pf);
free_rportfwd(pf);
}
}
@ -3611,6 +3674,21 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
portfwd_strptr = cfg->portfwd;
if (!ssh->portfwds) {
ssh->portfwds = newtree234(ssh_portcmp);
} else {
/*
* Go through the existing port forwardings and tag them
* with keep==FALSE. Any that we want to keep will be
* re-enabled as we go through the configuration and find
* out which bits are the same as they were before.
*/
struct ssh_portfwd *epf;
int i;
for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
epf->keep = FALSE;
}
while (*portfwd_strptr) {
type = *portfwd_strptr++;
saddr[0] = '\0';
@ -3680,13 +3758,33 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
}
if (sport && dport) {
/* Set up a description of the source port. */
static char *sportdesc;
struct ssh_portfwd *pfrec, *epfrec;
char *sportdesc;
sportdesc = dupprintf("%.*s%.*s%.*s%.*s%d%.*s",
(int)(*saddr?strlen(saddr):0), *saddr?saddr:NULL,
(int)(*saddr?1:0), ":",
(int)(sserv ? strlen(sports) : 0), sports,
sserv, "(", sport, sserv, ")");
if (type == 'L') {
pfrec = snew(struct ssh_portfwd);
pfrec->type = type;
pfrec->saddr = *saddr ? dupstr(saddr) : NULL;
pfrec->sport = sport;
pfrec->daddr = dupstr(host);
pfrec->dport = dport;
pfrec->local = NULL;
pfrec->remote = NULL;
epfrec = add234(ssh->portfwds, pfrec);
if (epfrec != pfrec) {
/*
* We already have a port forwarding with precisely
* these parameters. Hence, no need to do anything;
* simply tag the existing one as `keep'.
*/
epfrec->keep = TRUE;
free_portfwd(pfrec);
} else if (type == 'L') {
/* Verbose description of the destination port */
char *dportdesc = dupprintf("%s:%.*s%.*s%d%.*s",
host,
@ -3694,7 +3792,8 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
dserv, "(", dport, dserv, ")");
const char *err = pfd_addforward(host, dport,
*saddr ? saddr : NULL,
sport, ssh, &ssh->cfg);
sport, ssh, &ssh->cfg,
&pfrec->local);
if (err) {
logeventf(ssh, "Local port %s forward to %s"
" failed: %s", sportdesc, dportdesc, err);
@ -3706,7 +3805,8 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
} else if (type == 'D') {
const char *err = pfd_addforward(NULL, -1,
*saddr ? saddr : NULL,
sport, ssh, &ssh->cfg);
sport, ssh, &ssh->cfg,
&pfrec->local);
if (err) {
logeventf(ssh, "Local port %s SOCKS dynamic forward"
" setup failed: %s", sportdesc, err);
@ -3744,6 +3844,8 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
pf->sportdesc = sportdesc;
sportdesc = NULL;
pfrec->remote = pf;
pf->pfrec = pfrec;
if (ssh->version == 1) {
send_packet(ssh, SSH1_CMSG_PORT_FORWARD_REQUEST,
@ -3778,6 +3880,78 @@ static void ssh_setup_portfwd(Ssh ssh, const Config *cfg)
sfree(sportdesc);
}
}
/*
* Now go through and destroy any port forwardings which were
* not re-enabled.
*/
{
struct ssh_portfwd *epf;
int i;
for (i = 0; (epf = index234(ssh->portfwds, i)) != NULL; i++)
if (!epf->keep) {
char *message;
message = dupprintf("%s port forwarding from %s%s%d",
epf->type == 'L' ? "local" :
epf->type == 'R' ? "remote" : "dynamic",
epf->saddr ? epf->saddr : "",
epf->saddr ? ":" : "",
epf->sport);
if (epf->type != 'D') {
char *msg2 = dupprintf("%s to %s:%d", message,
epf->daddr, epf->dport);
sfree(message);
message = msg2;
}
logeventf(ssh, "Cancelling %s", message);
sfree(message);
if (epf->remote) {
struct ssh_rportfwd *rpf = epf->remote;
struct Packet *pktout;
/*
* Cancel the port forwarding at the server
* end.
*/
if (ssh->version == 1) {
/*
* We cannot cancel listening ports on the
* server side in SSH1! There's no message
* to support it. Instead, we simply remove
* the rportfwd record from the local end
* so that any connections the server tries
* to make on it are rejected.
*/
} else {
pktout = ssh2_pkt_init(SSH2_MSG_GLOBAL_REQUEST);
ssh2_pkt_addstring(pktout, "cancel-tcpip-forward");
ssh2_pkt_addbool(pktout, 0);/* _don't_ want reply */
if (epf->saddr) {
ssh2_pkt_addstring(pktout, epf->saddr);
} else if (ssh->cfg.rport_acceptall) {
ssh2_pkt_addstring(pktout, "0.0.0.0");
} else {
ssh2_pkt_addstring(pktout, "127.0.0.1");
}
ssh2_pkt_adduint32(pktout, epf->sport);
ssh2_pkt_send(ssh, pktout);
}
del234(ssh->rportfwds, rpf);
free_rportfwd(rpf);
} else if (epf->local) {
pfd_terminate(epf->local);
}
delpos234(ssh->portfwds, i);
free_portfwd(epf);
i--; /* so we don't skip one in the list */
}
}
}
static void ssh1_smsg_stdout_stderr_data(Ssh ssh, struct Packet *pktin)
@ -7281,17 +7455,12 @@ static void ssh_free(void *handle)
/*
* Reconfigure the SSH backend.
*
* Currently, this function does nothing very useful. In future,
* however, we could do some handy things with it. For example, we
* could make the port forwarding configurer active in the Change
* Settings box, and this routine could close down existing
* forwardings and open up new ones in response to changes.
*/
static void ssh_reconfig(void *handle, Config *cfg)
{
Ssh ssh = (Ssh) handle;
pinger_reconfig(ssh->pinger, &ssh->cfg, cfg);
ssh_setup_portfwd(ssh, cfg);
ssh->cfg = *cfg; /* STRUCTURE COPY */
}