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Move alloc_channel_id into sshcommon.c.

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That function _did_ depend on ssh.c's internal facilities, namely the
layout of 'struct ssh_channel'. In place of that, it now takes an
extra integer argument telling it where to find the channel id in
whatever data structure you give it a tree of - so now I can split up
the SSH-1 and SSH-2 channel handling without losing the services of
that nice channel-number allocator.
This commit is contained in:
Simon Tatham 2018-09-19 20:37:12 +01:00
parent 12abb95394
commit 968252bbdc
3 changed files with 46 additions and 33 deletions
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34
ssh.c
View File

@ -814,38 +814,6 @@ static int ssh_rportcmp_ssh2(void *av, void *bv)
return 0;
}
static unsigned alloc_channel_id(Ssh ssh)
{
const unsigned CHANNEL_NUMBER_OFFSET = 256;
search234_state ss;
/*
* First-fit allocation of channel numbers: we always pick the
* lowest unused one.
*
* Every channel before that, and no channel after it, has an ID
* exactly equal to its tree index plus CHANNEL_NUMBER_OFFSET. So
* we can use the search234 system to identify the length of that
* initial sequence, in a single log-time pass down the channels
* tree.
*/
search234_start(&ss, ssh->channels);
while (ss.element) {
struct ssh_channel *c = (struct ssh_channel *)ss.element;
if (c->localid == ss.index + CHANNEL_NUMBER_OFFSET)
search234_step(&ss, +1);
else
search234_step(&ss, -1);
}
/*
* Now ss.index gives exactly the number of channels in that
* initial sequence. So adding CHANNEL_NUMBER_OFFSET to it must
* give precisely the lowest unused channel number.
*/
return ss.index + CHANNEL_NUMBER_OFFSET;
}
static void c_write_stderr(int trusted, const void *vbuf, int len)
{
const char *buf = (const char *)vbuf;
@ -5676,7 +5644,7 @@ static int ssh_is_simple(Ssh ssh)
static void ssh_channel_init(struct ssh_channel *c)
{
Ssh ssh = c->ssh;
c->localid = alloc_channel_id(ssh);
c->localid = alloc_channel_id(ssh->channels, struct ssh_channel);
c->closes = 0;
c->pending_eof = FALSE;
c->throttling_conn = FALSE;

8
ssh.h
View File

@ -1326,3 +1326,11 @@ enum { SSH_IMPL_BUG_LIST(TMP_DECLARE_REAL_ENUM) };
void write_ttymodes_to_packet_from_conf(
BinarySink *bs, Frontend *frontend, Conf *conf,
int ssh_version, int ospeed, int ispeed);
/* Shared system for allocating local SSH channel ids. Expects to be
* passed a tree full of structs that have a field called 'localid' of
* type unsigned, and will check that! */
unsigned alloc_channel_id_general(tree234 *channels, size_t localid_offset);
#define alloc_channel_id(tree, type) \
TYPECHECK(&((type *)0)->localid == (unsigned *)0, \
alloc_channel_id_general(tree, offsetof(type, localid)))

37
sshcommon.c
View File

@ -466,3 +466,40 @@ void write_ttymodes_to_packet_from_conf(
put_uint32(bs, ospeed);
put_byte(bs, SSH_TTY_OP_END);
}
/* ----------------------------------------------------------------------
* Routine for allocating a new channel ID, given a means of finding
* the index field in a given channel structure.
*/
unsigned alloc_channel_id_general(tree234 *channels, size_t localid_offset)
{
const unsigned CHANNEL_NUMBER_OFFSET = 256;
search234_state ss;
/*
* First-fit allocation of channel numbers: we always pick the
* lowest unused one.
*
* Every channel before that, and no channel after it, has an ID
* exactly equal to its tree index plus CHANNEL_NUMBER_OFFSET. So
* we can use the search234 system to identify the length of that
* initial sequence, in a single log-time pass down the channels
* tree.
*/
search234_start(&ss, channels);
while (ss.element) {
unsigned localid = *(unsigned *)((char *)ss.element + localid_offset);
if (localid == ss.index + CHANNEL_NUMBER_OFFSET)
search234_step(&ss, +1);
else
search234_step(&ss, -1);
}
/*
* Now ss.index gives exactly the number of channels in that
* initial sequence. So adding CHANNEL_NUMBER_OFFSET to it must
* give precisely the lowest unused channel number.
*/
return ss.index + CHANNEL_NUMBER_OFFSET;
}