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apache / httpd / 5422fe57879e6867ad06b52ba861ded9b7dd0b91 / . / modules / ssl / ssl_scache_shmcb.c
blob: e588f0a5d11f083d43accd91960afe8367b434c3 [file] [log] [blame]
/* _ _
** _ __ ___ ___ __| | ___ ___| | mod_ssl
** | '_ ` _ \ / _ \ / _` | / __/ __| | Apache Interface to OpenSSL
** | | | | | | (_) | (_| | \__ \__ \ | www.modssl.org
** |_| |_| |_|\___/ \__,_|___|___/___/_| ftp.modssl.org
** |_____|
** ssl_scache_shmcb.c
** Session Cache via Shared Memory (Cyclic Buffer Variant)
*/
/* ====================================================================
* Copyright (c) 2000-2001 Ralf S. Engelschall. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following
* disclaimer in the documentation and/or other materials
* provided with the distribution.
*
* 3. All advertising materials mentioning features or use of this
* software must display the following acknowledgment:
* "This product includes software developed by
* Ralf S. Engelschall <rse@engelschall.com> for use in the
* mod_ssl project (http://www.modssl.org/)."
*
* 4. The names "mod_ssl" must not be used to endorse or promote
* products derived from this software without prior written
* permission. For written permission, please contact
* rse@engelschall.com.
*
* 5. Products derived from this software may not be called "mod_ssl"
* nor may "mod_ssl" appear in their names without prior
* written permission of Ralf S. Engelschall.
*
* 6. Redistributions of any form whatsoever must retain the following
* acknowledgment:
* "This product includes software developed by
* Ralf S. Engelschall <rse@engelschall.com> for use in the
* mod_ssl project (http://www.modssl.org/)."
*
* THIS SOFTWARE IS PROVIDED BY RALF S. ENGELSCHALL ``AS IS'' AND ANY
* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RALF S. ENGELSCHALL OR
* HIS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
* ====================================================================
*/
#include "mod_ssl.h"
/*
* This shared memory based SSL session cache implementation was
* originally written by Geoff Thorpe <geoff@eu.c2.net> for C2Net Europe
* and as a contribution to Ralf Engelschall's mod_ssl project.
*/
/*
* The shared-memory segment header can be cast to and from the
* SHMCBHeader type, all other structures need to be initialised by
* utility functions.
*
* The "header" looks like this;
*
* data applying to the overall structure:
* - division_offset (unsigned int):
* how far into the shared memory segment the first division is.
* - division_size (unsigned int):
* how many bytes each division occupies.
* (NB: This includes the queue and the cache)
* - division_mask (unsigned char):
* the "mask" in the next line. Add one to this,
* and that's the number of divisions.
*
* data applying to within each division:
* - queue_size (unsigned int):
* how big each "queue" is. NB: The queue is the first block in each
* division and is followed immediately by the cache itself so so
* there's no cache_offset value.
*
* data applying to within each queue:
* - index_num (unsigned char):
* how many indexes in each cache's queue
* - index_offset (unsigned char):
* how far into the queue the first index is.
* - index_size:
* how big each index is.
*
* data applying to within each cache:
* - cache_data_offset (unsigned int):
* how far into the cache the session-data array is stored.
* - cache_data_size (unsigned int):
* how big each cache's data block is.
*
* statistics data (this will eventually be per-division but right now
* there's only one mutex):
* - stores (unsigned long):
* how many stores have been performed in the cache.
* - expiries (unsigned long):
* how many session have been expired from the cache.
* - scrolled (unsigned long):
* how many sessions have been scrolled out of full cache during a
* "store" operation. This is different to the "removes" stats as
* they are requested by mod_ssl/Apache, these are done because of
* cache logistics. (NB: Also, this value should be deducible from
* the others if my code has no bugs, but I count it anyway - plus
* it helps debugging :-).
* - retrieves_hit (unsigned long):
* how many session-retrieves have succeeded.
* - retrieves_miss (unsigned long):
* how many session-retrieves have failed.
* - removes_hit (unsigned long):
* - removes_miss (unsigned long):
*
* Following immediately after the header is an array of "divisions".
* Each division is simply a "queue" immediately followed by its
* corresponding "cache". Each division handles some pre-defined band
* of sessions by using the "division_mask" in the header. Eg. if
* division_mask=0x1f then there are 32 divisions, the first of which
* will store sessions whose least-significant 5 bits are 0, the second
* stores session whose LS 5 bits equal 1, etc. A queue is an indexing
* structure referring to its corresponding cache.
*
* A "queue" looks like this;
*
* - first_pos (unsigned int):
* the location within the array of indexes where the virtual
* "left-hand-edge" of the cyclic buffer is.
* - pos_count (unsigned int):
* the number of indexes occupied from first_pos onwards.
*
* ...followed by an array of indexes, each of which can be
* memcpy'd to and from an SHMCBIndex, and look like this;
*
* - expires (time_t):
* the time() value at which this session expires.
* - offset (unsigned int):
* the offset within the cache data block where the corresponding
* session is stored.
* - s_id2 (unsigned char):
* the second byte of the session_id, stored as an optimisation to
* reduce the number of d2i_SSL_SESSION calls that are made when doing
* a lookup.
* - removed (unsigned char):
* a byte used to indicate whether a session has been "passively"
* removed. Ie. it is still in the cache but is to be disregarded by
* any "retrieve" operation.
*
* A "cache" looks like this;
*
* - first_pos (unsigned int):
* the location within the data block where the virtual
* "left-hand-edge" of the cyclic buffer is.
* - pos_count (unsigned int):
* the number of bytes used in the data block from first_pos onwards.
*
* ...followed by the data block in which actual DER-encoded SSL
* sessions are stored.
*/
/*
* Header - can be memcpy'd to and from the front of the shared
* memory segment. NB: The first copy (commented out) has the
* elements in a meaningful order, but due to data-alignment
* braindeadness, the second (uncommented) copy has the types grouped
* so as to decrease "struct-bloat". sigh.
*/
typedef struct {
#if 0
unsigned char division_mask;
unsigned int division_offset;
unsigned int division_size;
unsigned int queue_size;
unsigned char index_num;
unsigned char index_offset;
unsigned char index_size;
unsigned int cache_data_offset;
unsigned int cache_data_size;
unsigned long num_stores;
unsigned long num_expiries;
unsigned long num_scrolled;
unsigned long num_retrieves_hit;
unsigned long num_retrieves_miss;
unsigned long num_removes_hit;
unsigned long num_removes_miss;
#else
unsigned long num_stores;
unsigned long num_expiries;
unsigned long num_scrolled;
unsigned long num_retrieves_hit;
unsigned long num_retrieves_miss;
unsigned long num_removes_hit;
unsigned long num_removes_miss;
unsigned int division_offset;
unsigned int division_size;
unsigned int queue_size;
unsigned int cache_data_offset;
unsigned int cache_data_size;
unsigned char division_mask;
unsigned char index_num;
unsigned char index_offset;
unsigned char index_size;
#endif
} SHMCBHeader;
/*
* Index - can be memcpy'd to and from an index inside each
* queue's index array.
*/
typedef struct {
time_t expires;
unsigned int offset;
unsigned char s_id2;
unsigned char removed;
} SHMCBIndex;
/*
* Queue - must be populated by a call to shmcb_get_division
* and the structure's pointers are used for updating (ie.
* the structure doesn't need any "set" to update values).
*/
typedef struct {
SHMCBHeader *header;
unsigned int *first_pos;
unsigned int *pos_count;
SHMCBIndex *indexes;
} SHMCBQueue;
/*
* Cache - same comment as for Queue. 'Queue's are in a 1-1
* correspondance with 'Cache's and are usually carried round
* in a pair, they are only seperated for clarity.
*/
typedef struct {
SHMCBHeader *header;
unsigned int *first_pos;
unsigned int *pos_count;
unsigned char *data;
} SHMCBCache;
/*
* Forward function prototypes.
*/
/* Functions for working around data-alignment-picky systems (sparcs,
Irix, etc). These use "memcpy" as a way of foxing these systems into
treating the composite types as byte-arrays rather than higher-level
primitives that it prefers to have 4-(or 8-)byte aligned. I don't
envisage this being a performance issue as a couple of 2 or 4 byte
memcpys can hardly make a dent on the massive memmove operations this
cache technique avoids, nor the overheads of ASN en/decoding. */
static unsigned int shmcb_get_safe_uint(unsigned int *);
static void shmcb_set_safe_uint(unsigned int *, unsigned int);
#if 0 /* Unused so far */
static unsigned long shmcb_get_safe_ulong(unsigned long *);
static void shmcb_set_safe_ulong(unsigned long *, unsigned long);
#endif
static time_t shmcb_get_safe_time(time_t *);
static void shmcb_set_safe_time(time_t *, time_t);
/* Underlying functions for session-caching */
static BOOL shmcb_init_memory(server_rec *, void *, unsigned int);
static BOOL shmcb_store_session(server_rec *, void *, UCHAR *, int, SSL_SESSION *, time_t);
static SSL_SESSION *shmcb_retrieve_session(server_rec *, void *, UCHAR *, int);
static BOOL shmcb_remove_session(server_rec *, void *, UCHAR *, int);
/* Utility functions for manipulating the structures */
static void shmcb_get_header(void *, SHMCBHeader **);
static BOOL shmcb_get_division(SHMCBHeader *, SHMCBQueue *, SHMCBCache *, unsigned int);
static SHMCBIndex *shmcb_get_index(const SHMCBQueue *, unsigned int);
static unsigned int shmcb_expire_division(server_rec *, SHMCBQueue *, SHMCBCache *);
static BOOL shmcb_insert_encoded_session(server_rec *, SHMCBQueue *, SHMCBCache *, unsigned char *, unsigned int, unsigned char *, time_t);
static SSL_SESSION *shmcb_lookup_session_id(server_rec *, SHMCBQueue *, SHMCBCache *, UCHAR *, int);
static BOOL shmcb_remove_session_id(server_rec *, SHMCBQueue *, SHMCBCache *, UCHAR *, int);
/*
* Data-alignment functions (a.k.a. avoidance tactics)
*
* NB: On HPUX (and possibly others) there is a *very* mischievous little
* "optimisation" in the compilers where it will convert the following;
* memcpy(dest_ptr, &source, sizeof(unsigned int));
* (where dest_ptr is of type (unsigned int *) and source is (unsigned int))
* into;
* *dest_ptr = source; (or *dest_ptr = *(&source), not sure).
* Either way, it completely destroys the whole point of these _safe_
* functions, because the assignment operation will fall victim to the
* architecture's byte-alignment dictations, whereas the memcpy (as a
* byte-by-byte copy) should not. sigh. So, if you're wondering about the
* apparently unnecessary conversions to (unsigned char *) in these
* functions, you now have an explanation. Don't just revert them back and
* say "ooh look, it still works" - if you try it on HPUX (well, 32-bit
* HPUX 11.00 at least) you may find it fails with a SIGBUS. :-(
*/
static unsigned int shmcb_get_safe_uint(unsigned int *ptr)
{
unsigned char *from;
unsigned int ret;
from = (unsigned char *)ptr;
memcpy(&ret, from, sizeof(unsigned int));
return ret;
}
static void shmcb_set_safe_uint(unsigned int *ptr, unsigned int val)
{
unsigned char *to, *from;
to = (unsigned char *)ptr;
from = (unsigned char *)(&val);
memcpy(to, from, sizeof(unsigned int));
}
#if 0 /* Unused so far */
static unsigned long shmcb_get_safe_ulong(unsigned long *ptr)
{
unsigned char *from;
unsigned long ret;
from = (unsigned char *)ptr;
memcpy(&ret, from, sizeof(unsigned long));
return ret;
}
static void shmcb_set_safe_ulong(unsigned long *ptr, unsigned long val)
{
unsigned char *to, *from;
to = (unsigned char *)ptr;
from = (unsigned char *)(&val);
memcpy(to, from, sizeof(unsigned long));
}
#endif
static time_t shmcb_get_safe_time(time_t * ptr)
{
unsigned char *from;
time_t ret;
from = (unsigned char *)ptr;
memcpy(&ret, from, sizeof(time_t));
return ret;
}
static void shmcb_set_safe_time(time_t * ptr, time_t val)
{
unsigned char *to, *from;
to = (unsigned char *)ptr;
from = (unsigned char *)(&val);
memcpy(to, from, sizeof(time_t));
}
/*
**
** High-Level "handlers" as per ssl_scache.c
**
*/
static void *shmcb_malloc(size_t size)
{
SSLModConfigRec *mc = myModConfig();
return ap_mm_malloc(mc->pSessionCacheDataMM, size);
}
void ssl_scache_shmcb_init(server_rec *s, pool *p)
{
SSLModConfigRec *mc = myModConfig();
AP_MM *mm;
void *shm_segment = NULL;
int avail, avail_orig;
/*
* Create shared memory segment
*/
if (mc->szSessionCacheDataFile == NULL) {
ssl_log(s, SSL_LOG_ERROR, "SSLSessionCache required");
ssl_die();
}
if ((mm = ap_mm_create(mc->nSessionCacheDataSize,
mc->szSessionCacheDataFile)) == NULL) {
ssl_log(s, SSL_LOG_ERROR,
"Cannot allocate shared memory: %s", ap_mm_error());
ssl_die();
}
mc->pSessionCacheDataMM = mm;
/*
* Make sure the child processes have access to the underlying files
*/
ap_mm_permission(mm, SSL_MM_FILE_MODE, ap_user_id, -1);
/*
* Create cache inside the shared memory segment
*/
avail = avail_orig = ap_mm_available(mm);
ssl_log(s, SSL_LOG_TRACE, "Shared-memory segment has %u available",
avail);
/*
* For some reason to do with MM's internal management, I can't
* allocate the full amount. Implement a reasonable form of trial
* and error and output trace information.
*/
while ((shm_segment == NULL) && ((avail_orig - avail) * 100 < avail_orig)) {
shm_segment = shmcb_malloc(avail);
if (shm_segment == NULL) {
ssl_log(s, SSL_LOG_TRACE,
"shmcb_malloc attempt for %u bytes failed", avail);
avail -= 2;
}
}
if (shm_segment == NULL) {
ssl_log(s, SSL_LOG_ERROR,
"Cannot allocate memory for the 'shmcb' session cache\n");
ssl_die();
}
ssl_log(s, SSL_LOG_TRACE, "shmcb_init allocated %u bytes of shared "
"memory", avail);
if (!shmcb_init_memory(s, shm_segment, avail)) {
ssl_log(s, SSL_LOG_ERROR,
"Failure initialising 'shmcb' shared memory");
ssl_die();
}
ssl_log(s, SSL_LOG_INFO, "Shared memory session cache initialised");
/*
* Success ... we hack the memory block into place by cheating for
* now and stealing a member variable the original shared memory
* cache was using. :-)
*/
mc->tSessionCacheDataTable = (table_t *) shm_segment;
return;
}
void ssl_scache_shmcb_kill(server_rec *s)
{
SSLModConfigRec *mc = myModConfig();
if (mc->pSessionCacheDataMM != NULL) {
ap_mm_destroy(mc->pSessionCacheDataMM);
mc->pSessionCacheDataMM = NULL;
}
return;
}
BOOL ssl_scache_shmcb_store(server_rec *s, UCHAR * id, int idlen,
time_t timeout, SSL_SESSION * pSession)
{
SSLModConfigRec *mc = myModConfig();
void *shm_segment;
BOOL to_return = FALSE;
/* We've kludged our pointer into the other cache's member variable. */
shm_segment = (void *) mc->tSessionCacheDataTable;
ssl_mutex_on(s);
if (!shmcb_store_session(s, shm_segment, id, idlen, pSession, timeout))
/* in this cache engine, "stores" should never fail. */
ssl_log(s, SSL_LOG_ERROR, "'shmcb' code was unable to store a "
"session in the cache.");
else {
ssl_log(s, SSL_LOG_TRACE, "shmcb_store successful");
to_return = TRUE;
}
ssl_mutex_off(s);
return to_return;
}
SSL_SESSION *ssl_scache_shmcb_retrieve(server_rec *s, UCHAR * id, int idlen)
{
SSLModConfigRec *mc = myModConfig();
void *shm_segment;
SSL_SESSION *pSession;
/* We've kludged our pointer into the other cache's member variable. */
shm_segment = (void *) mc->tSessionCacheDataTable;
ssl_mutex_on(s);
pSession = shmcb_retrieve_session(s, shm_segment, id, idlen);
ssl_mutex_off(s);
if (pSession)
ssl_log(s, SSL_LOG_TRACE, "shmcb_retrieve had a hit");
else {
ssl_log(s, SSL_LOG_TRACE, "shmcb_retrieve had a miss");
ssl_log(s, SSL_LOG_INFO, "Client requested a 'session-resume' but "
"we have no such session.");
}
return pSession;
}
void ssl_scache_shmcb_remove(server_rec *s, UCHAR * id, int idlen)
{
SSLModConfigRec *mc = myModConfig();
void *shm_segment;
/* We've kludged our pointer into the other cache's member variable. */
shm_segment = (void *) mc->tSessionCacheDataTable;
shmcb_remove_session(s, shm_segment, id, idlen);
}
void ssl_scache_shmcb_expire(server_rec *s)
{
/* NOP */
return;
}
void ssl_scache_shmcb_status(server_rec *s, pool *p,
void (*func) (char *, void *), void *arg)
{
SSLModConfigRec *mc = myModConfig();
SHMCBHeader *header;
SHMCBQueue queue;
SHMCBCache cache;
SHMCBIndex *idx;
void *shm_segment;
unsigned int loop, total, cache_total, non_empty_divisions;
int index_pct, cache_pct;
double expiry_total;
time_t average_expiry, now, max_expiry, min_expiry, idxexpiry;
ssl_log(s, SSL_LOG_TRACE, "inside ssl_scache_shmcb_status");
/* We've kludged our pointer into the other cache's member variable. */
shm_segment = (void *) mc->tSessionCacheDataTable;
/* Get the header structure. */
shmcb_get_header(shm_segment, &header);
total = cache_total = non_empty_divisions = 0;
average_expiry = max_expiry = min_expiry = 0;
expiry_total = 0;
/* It may seem strange to grab "now" at this point, but in theory
* we should never have a negative threshold but grabbing "now" after
* the loop (which performs expiries) could allow that chance. */
now = time(NULL);
for (loop = 0; loop <= header->division_mask; loop++) {
if (shmcb_get_division(header, &queue, &cache, loop)) {
shmcb_expire_division(s, &queue, &cache);
total += shmcb_get_safe_uint(queue.pos_count);
cache_total += shmcb_get_safe_uint(cache.pos_count);
if (shmcb_get_safe_uint(queue.pos_count) > 0) {
idx = shmcb_get_index(&queue,
shmcb_get_safe_uint(queue.first_pos));
non_empty_divisions++;
idxexpiry = shmcb_get_safe_time(&(idx->expires));
expiry_total += (double) idxexpiry;
max_expiry = (idxexpiry > max_expiry ? idxexpiry :
max_expiry);
if (min_expiry == 0)
min_expiry = idxexpiry;
else
min_expiry = (idxexpiry < min_expiry ? idxexpiry :
min_expiry);
}
}
}
index_pct = (100 * total) / (header->index_num * (header->division_mask + 1));
cache_pct = (100 * cache_total) / (header->cache_data_size * (header->division_mask + 1));
func(ap_psprintf(p, "cache type: <b>SHMCB</b>, shared memory: <b>%d</b> "
"bytes, current sessions: <b>%d</b><br>",
mc->nSessionCacheDataSize, total), arg);
func(ap_psprintf(p, "sub-caches: <b>%d</b>, indexes per sub-cache: "
"<b>%d</b><br>", (int) header->division_mask + 1,
(int) header->index_num), arg);
if (non_empty_divisions != 0) {
average_expiry = (time_t)(expiry_total / (double)non_empty_divisions);
func(ap_psprintf(p, "time left on oldest entries' SSL sessions: "), arg);
if (now < average_expiry)
func(ap_psprintf(p, "avg: <b>%d</b> seconds, (range: %d...%d)<br>",
(int)(average_expiry - now), (int) (min_expiry - now),
(int)(max_expiry - now)), arg);
else
func(ap_psprintf(p, "expiry threshold: <b>Calculation Error!</b>"
"<br>"), arg);
}
func(ap_psprintf(p, "index usage: <b>%d%%</b>, cache usage: <b>%d%%</b>"
"<br>", index_pct, cache_pct), arg);
func(ap_psprintf(p, "total sessions stored since starting: <b>%lu</b><br>",
header->num_stores), arg);
func(ap_psprintf(p, "total sessions expired since starting: <b>%lu</b><br>",
header->num_expiries), arg);
func(ap_psprintf(p, "total (pre-expiry) sessions scrolled out of the "
"cache: <b>%lu</b><br>", header->num_scrolled), arg);
func(ap_psprintf(p, "total retrieves since starting: <b>%lu</b> hit, "
"<b>%lu</b> miss<br>", header->num_retrieves_hit,
header->num_retrieves_miss), arg);
func(ap_psprintf(p, "total removes since starting: <b>%lu</b> hit, "
"<b>%lu</b> miss<br>", header->num_removes_hit,
header->num_removes_miss), arg);
ssl_log(s, SSL_LOG_TRACE, "leaving shmcb_status");
return;
}
/*
**
** Memory manipulation and low-level cache operations
**
*/
static BOOL shmcb_init_memory(
server_rec *s, void *shm_mem,
unsigned int shm_mem_size)
{
SHMCBHeader *header;
SHMCBQueue queue;
SHMCBCache cache;
unsigned int temp, loop, granularity;
ssl_log(s, SSL_LOG_TRACE, "entered shmcb_init_memory()");
/* Calculate some sizes... */
temp = sizeof(SHMCBHeader);
/* If the segment is ridiculously too small, bail out */
if (shm_mem_size < (2*temp)) {
ssl_log(s, SSL_LOG_ERROR, "shared memory segment too small");
return FALSE;
}
/* Make temp the amount of memory without the header */
temp = shm_mem_size - temp;
/* Work on the basis that you need 10 bytes index for each session
* (approx 150 bytes), which is to divide temp by 160 - and then
* make sure we err on having too index space to burn even when
* the cache is full, which is a lot less stupid than having
* having not enough index space to utilise the whole cache!. */
temp /= 120;
ssl_log(s, SSL_LOG_TRACE, "for %u bytes, recommending %u indexes",
shm_mem_size, temp);
/* We should divide these indexes evenly amongst the queues. Try
* to get it so that there are roughly half the number of divisions
* as there are indexes in each division. */
granularity = 256;
while ((temp / granularity) < (2 * granularity))
granularity /= 2;
/* So we have 'granularity' divisions, set 'temp' equal to the
* number of indexes in each division. */
temp /= granularity;
/* Too small? Bail ... */
if (temp < 5) {
ssl_log(s, SSL_LOG_ERROR, "shared memory segment too small");
return FALSE;
}
/* OK, we're sorted - from here on in, the return should be TRUE */
header = (SHMCBHeader *)shm_mem;
header->division_mask = (unsigned char)(granularity - 1);
header->division_offset = sizeof(SHMCBHeader);
header->index_num = temp;
header->index_offset = (2 * sizeof(unsigned int));
header->index_size = sizeof(SHMCBIndex);
header->queue_size = header->index_offset +
(header->index_num * header->index_size);
/* Now calculate the space for each division */
temp = shm_mem_size - header->division_offset;
header->division_size = temp / granularity;
/* Calculate the space left in each division for the cache */
temp -= header->queue_size;
header->cache_data_offset = (2 * sizeof(unsigned int));
header->cache_data_size = header->division_size -
header->queue_size - header->cache_data_offset;
/* Output trace info */
ssl_log(s, SSL_LOG_TRACE, "shmcb_init_memory choices follow");
ssl_log(s, SSL_LOG_TRACE, "division_mask = 0x%02X", header->division_mask);
ssl_log(s, SSL_LOG_TRACE, "division_offset = %u", header->division_offset);
ssl_log(s, SSL_LOG_TRACE, "division_size = %u", header->division_size);
ssl_log(s, SSL_LOG_TRACE, "queue_size = %u", header->queue_size);
ssl_log(s, SSL_LOG_TRACE, "index_num = %u", header->index_num);
ssl_log(s, SSL_LOG_TRACE, "index_offset = %u", header->index_offset);
ssl_log(s, SSL_LOG_TRACE, "index_size = %u", header->index_size);
ssl_log(s, SSL_LOG_TRACE, "cache_data_offset = %u", header->cache_data_offset);
ssl_log(s, SSL_LOG_TRACE, "cache_data_size = %u", header->cache_data_size);
/* The header is done, make the caches empty */
for (loop = 0; loop < granularity; loop++) {
if (!shmcb_get_division(header, &queue, &cache, loop))
ssl_log(s, SSL_LOG_ERROR, "shmcb_init_memory, " "internal error");
shmcb_set_safe_uint(cache.first_pos, 0);
shmcb_set_safe_uint(cache.pos_count, 0);
shmcb_set_safe_uint(queue.first_pos, 0);
shmcb_set_safe_uint(queue.pos_count, 0);
}
ssl_log(s, SSL_LOG_TRACE, "leaving shmcb_init_memory()");
return TRUE;
}
static BOOL shmcb_store_session(
server_rec *s, void *shm_segment, UCHAR * id,
int idlen, SSL_SESSION * pSession,
time_t timeout)
{
SHMCBHeader *header;
SHMCBQueue queue;
SHMCBCache cache;
unsigned char masked_index;
unsigned char encoded[SSL_SESSION_MAX_DER];
unsigned char *ptr_encoded;
unsigned int len_encoded;
time_t expiry_time;
ssl_log(s, SSL_LOG_TRACE, "inside shmcb_store_session");
/* Get the header structure, which division this session will fall into etc. */
shmcb_get_header(shm_segment, &header);
masked_index = pSession->session_id[0] & header->division_mask;
ssl_log(s, SSL_LOG_TRACE, "session_id[0]=%u, masked index=%u",
pSession->session_id[0], masked_index);
if (!shmcb_get_division(header, &queue, &cache, (unsigned int)masked_index)) {
ssl_log(s, SSL_LOG_ERROR, "shmcb_store_session, " "internal error");
return FALSE;
}
/* Serialise the session, work out how much we're dealing
* with. NB: This check could be removed if we're not paranoid
* or we find some assurance that it will never be necessary. */
len_encoded = i2d_SSL_SESSION(pSession, NULL);
if (len_encoded > SSL_SESSION_MAX_DER) {
ssl_log(s, SSL_LOG_ERROR, "session is too big (%u bytes)",
len_encoded);
return FALSE;
}
ptr_encoded = encoded;
len_encoded = i2d_SSL_SESSION(pSession, &ptr_encoded);
expiry_time = timeout;
if (!shmcb_insert_encoded_session(s, &queue, &cache, encoded,
len_encoded, pSession->session_id,
expiry_time)) {
ssl_log(s, SSL_LOG_ERROR, "can't store a session!");
return FALSE;
}
ssl_log(s, SSL_LOG_TRACE, "leaving shmcb_store successfully");
header->num_stores++;
return TRUE;
}
static SSL_SESSION *shmcb_retrieve_session(
server_rec *s, void *shm_segment,
UCHAR * id, int idlen)
{
SHMCBHeader *header;
SHMCBQueue queue;
SHMCBCache cache;
unsigned char masked_index;
SSL_SESSION *pSession;
ssl_log(s, SSL_LOG_TRACE, "inside shmcb_retrieve_session");
if (idlen < 2) {
ssl_log(s, SSL_LOG_ERROR, "unusably short session_id provided "
"(%u bytes)", idlen);
return FALSE;
}
/* Get the header structure, which division this session lookup
* will come from etc. */
shmcb_get_header(shm_segment, &header);
masked_index = id[0] & header->division_mask;
ssl_log(s, SSL_LOG_TRACE, "id[0]=%u, masked index=%u", id[0],
masked_index);
if (!shmcb_get_division(header, &queue, &cache, (unsigned int) masked_index)) {
ssl_log(s, SSL_LOG_ERROR, "shmcb_retrieve_session, " "internal error");
header->num_retrieves_miss++;
return FALSE;
}
/* Get the session corresponding to the session_id or NULL if it
* doesn't exist (or is flagged as "removed"). */
pSession = shmcb_lookup_session_id(s, &queue, &cache, id, idlen);
if (pSession)
header->num_retrieves_hit++;
else
header->num_retrieves_miss++;
ssl_log(s, SSL_LOG_TRACE, "leaving shmcb_retrieve_session");
return pSession;
}
static BOOL shmcb_remove_session(
server_rec *s, void *shm_segment,
UCHAR * id, int idlen)
{
SHMCBHeader *header;
SHMCBQueue queue;
SHMCBCache cache;
unsigned char masked_index;
BOOL res;
ssl_log(s, SSL_LOG_TRACE, "inside shmcb_remove_session");
if (id == NULL) {
ssl_log(s, SSL_LOG_ERROR, "remove called with NULL session_id!");
return FALSE;
}
/* Get the header structure, which division this session remove
* will happen in etc. */
shmcb_get_header(shm_segment, &header);
masked_index = id[0] & header->division_mask;
ssl_log(s, SSL_LOG_TRACE, "id[0]=%u, masked index=%u",
id[0], masked_index);
if (!shmcb_get_division(header, &queue, &cache, (unsigned int)masked_index)) {
ssl_log(s, SSL_LOG_ERROR, "shmcb_remove_session, internal error");
header->num_removes_miss++;
return FALSE;
}
res = shmcb_remove_session_id(s, &queue, &cache, id, idlen);
if (res)
header->num_removes_hit++;
else
header->num_removes_miss++;
ssl_log(s, SSL_LOG_TRACE, "leaving shmcb_remove_session");
return res;
}
/*
**
** Weirdo cyclic buffer functions
**
*/
/* This gets used in the cyclic "index array" (in the 'Queue's) and
* in the cyclic 'Cache's too ... you provide the "width" of the
* cyclic store, the starting position and how far to move (with
* wrapping if necessary). Basically it's addition modulo buf_size. */
static unsigned int shmcb_cyclic_increment(
unsigned int buf_size,
unsigned int start_pos,
unsigned int to_add)
{
start_pos += to_add;
while (start_pos >= buf_size)
start_pos -= buf_size;
return start_pos;
}
/* Given two positions in a cyclic buffer, calculate the "distance".
* This is to cover the case ("non-trivial") where the 'next' offset
* is to the left of the 'start' offset. NB: This calculates the
* space inclusive of one end-point but not the other. There is an
* ambiguous case (which is why we use the <start_pos,offset>
* coordinate system rather than <start_pos,end_pos> one) when 'start'
* is the same as 'next'. It could indicate the buffer is full or it
* can indicate the buffer is empty ... I choose the latter as it's
* easier and usually necessary to check if the buffer is full anyway
* before doing incremental logic (which is this useful for), but we
* definitely need the empty case handled - in fact it's our starting
* state!! */
static unsigned int shmcb_cyclic_space(
unsigned int buf_size,
unsigned int start_offset,
unsigned int next_offset)
{
/* Is it the trivial case? */
if (start_offset <= next_offset)
return (next_offset - start_offset); /* yes */
else
return ((buf_size - start_offset) + next_offset); /* no */
}
/* A "normal-to-cyclic" memcpy ... this takes a linear block of
* memory and copies it onto a cyclic buffer. The purpose and
* function of this is pretty obvious, you need to cover the case
* that the destination (cyclic) buffer has to wrap round. */
static void shmcb_cyclic_ntoc_memcpy(
unsigned int buf_size,
unsigned char *data,
unsigned int dest_offset,
unsigned char *src, unsigned int src_len)
{
/* Can it be copied all in one go? */
if (dest_offset + src_len < buf_size)
/* yes */
memcpy(data + dest_offset, src, src_len);
else {
/* no */
memcpy(data + dest_offset, src, buf_size - dest_offset);
memcpy(data, src + buf_size - dest_offset,
src_len + dest_offset - buf_size);
}
return;
}
/* A "cyclic-to-normal" memcpy ... given the last function, this
* one's purpose is clear, it copies out of a cyclic buffer handling
* wrapping. */
static void shmcb_cyclic_cton_memcpy(
unsigned int buf_size,
unsigned char *dest,
unsigned char *data,
unsigned int src_offset,
unsigned int src_len)
{
/* Can it be copied all in one go? */
if (src_offset + src_len < buf_size)
/* yes */
memcpy(dest, data + src_offset, src_len);
else {
/* no */
memcpy(dest, data + src_offset, buf_size - src_offset);
memcpy(dest + buf_size - src_offset, data,
src_len + src_offset - buf_size);
}
return;
}
/* Here's the cool hack that makes it all work ... by simply
* making the first collection of bytes *be* our header structure
* (casting it into the C structure), we have the perfect way to
* maintain state in a shared-memory session cache from one call
* (and process) to the next, use the shared memory itself! The
* original mod_ssl shared-memory session cache uses variables
* inside the context, but we simply use that for storing the
* pointer to the shared memory itself. And don't forget, after
* Apache's initialisation, this "header" is constant/read-only
* so we can read it outside any locking.
* <grin> - sometimes I just *love* coding y'know?! */
static void shmcb_get_header(void *shm_mem, SHMCBHeader **header)
{
*header = (SHMCBHeader *)shm_mem;
return;
}
/* This is what populates our "interesting" structures. Given a
* pointer to the header, and an index into the appropriate
* division (this must have already been masked using the
* division_mask by the caller!), we can populate the provided
* SHMCBQueue and SHMCBCache structures with values and
* pointers to the underlying shared memory. Upon returning
* (if not FALSE), the caller can meddle with the pointer
* values and they will map into the shared-memory directly,
* as such there's no need to "free" or "set" the Queue or
* Cache values, they were themselves references to the *real*
* data. */
static BOOL shmcb_get_division(
SHMCBHeader *header, SHMCBQueue *queue,
SHMCBCache *cache, unsigned int idx)
{
unsigned char *pQueue;
unsigned char *pCache;
/* bounds check */
if (idx > (unsigned int) header->division_mask)
return FALSE;
/* Locate the blocks of memory storing the corresponding data */
pQueue = ((unsigned char *) header) + header->division_offset +
(idx * header->division_size);
pCache = pQueue + header->queue_size;
/* Populate the structures with appropriate pointers */
queue->first_pos = (unsigned int *) pQueue;
/* Our structures stay packed, no matter what the system's
* data-alignment regime is. */
queue->pos_count = (unsigned int *) (pQueue + sizeof(unsigned int));
queue->indexes = (SHMCBIndex *) (pQueue + (2 * sizeof(unsigned int)));
cache->first_pos = (unsigned int *) pCache;
cache->pos_count = (unsigned int *) (pCache + sizeof(unsigned int));
cache->data = (unsigned char *) (pCache + (2 * sizeof(unsigned int)));
queue->header = cache->header = header;
return TRUE;
}
/* This returns a pointer to the piece of shared memory containing
* a specified 'Index'. SHMCBIndex, like SHMCBHeader, is a fixed
* width non-referencing structure of primitive types that can be
* cast onto the corresponding block of shared memory. Thus, by
* returning a cast pointer to that section of shared memory, the
* caller can read and write values to and from the "structure" and
* they are actually reading and writing the underlying shared
* memory. */
static SHMCBIndex *shmcb_get_index(
const SHMCBQueue *queue, unsigned int idx)
{
/* bounds check */
if (idx > (unsigned int) queue->header->index_num)
return NULL;
/* Return a pointer to the index. NB: I am being horribly pendantic
* here so as to avoid any potential data-alignment assumptions being
* placed on the pointer arithmetic by the compiler (sigh). */
return (SHMCBIndex *)(((unsigned char *) queue->indexes) +
(idx * sizeof(SHMCBIndex)));
}
/* This functions rolls expired cache (and index) entries off the front
* of the cyclic buffers in a division. The function returns the number
* of expired sessions. */
static unsigned int shmcb_expire_division(
server_rec *s, SHMCBQueue *queue, SHMCBCache *cache)
{
SHMCBIndex *idx;
time_t now;
unsigned int loop, index_num, pos_count, new_pos;
SHMCBHeader *header;
ssl_log(s, SSL_LOG_TRACE, "entering shmcb_expire_division");
/* We must calculate num and space ourselves based on expiry times. */
now = time(NULL);
loop = 0;
new_pos = shmcb_get_safe_uint(queue->first_pos);
/* Cache useful values */
header = queue->header;
index_num = header->index_num;
pos_count = shmcb_get_safe_uint(queue->pos_count);
while (loop < pos_count) {
idx = shmcb_get_index(queue, new_pos);
if (shmcb_get_safe_time(&(idx->expires)) > now)
/* it hasn't expired yet, we're done iterating */
break;
/* This one should be expired too. Shift to the next entry. */
loop++;
new_pos = shmcb_cyclic_increment(index_num, new_pos, 1);
}
/* Find the new_offset and make the expiries happen. */
if (loop > 0) {
ssl_log(s, SSL_LOG_TRACE, "will be expiring %u sessions", loop);
/* We calculate the new_offset by "peeking" (or in the
* case it's the last entry, "sneaking" ;-). */
if (loop == pos_count) {
/* We are expiring everything! This is easy to do... */
shmcb_set_safe_uint(queue->pos_count, 0);
shmcb_set_safe_uint(cache->pos_count, 0);
}
else {
/* The Queue is easy to adjust */
shmcb_set_safe_uint(queue->pos_count,
shmcb_get_safe_uint(queue->pos_count) - loop);
shmcb_set_safe_uint(queue->first_pos, new_pos);
/* peek to the start of the next session */
idx = shmcb_get_index(queue, new_pos);
/* We can use shmcb_cyclic_space because we've guaranteed
* we don't fit the ambiguous full/empty case. */
shmcb_set_safe_uint(cache->pos_count,
shmcb_get_safe_uint(cache->pos_count) -
shmcb_cyclic_space(header->cache_data_size,
shmcb_get_safe_uint(cache->first_pos),
shmcb_get_safe_uint(&(idx->offset))));
shmcb_set_safe_uint(cache->first_pos, shmcb_get_safe_uint(&(idx->offset)));
}
ssl_log(s, SSL_LOG_TRACE, "we now have %u sessions",
shmcb_get_safe_uint(queue->pos_count));
}
header->num_expiries += loop;
return loop;
}
/* Inserts a new encoded session into a queue/cache pair - expiring
* (early or otherwise) any leading sessions as necessary to ensure
* there is room. An error return (FALSE) should only happen in the
* event of surreal values being passed on, or ridiculously small
* cache sizes. NB: For tracing purposes, this function is also given
* the server_rec to allow "ssl_log()". */
static BOOL shmcb_insert_encoded_session(
server_rec *s, SHMCBQueue * queue,
SHMCBCache * cache,
unsigned char *encoded,
unsigned int encoded_len,
unsigned char *session_id,
time_t expiry_time)
{
SHMCBHeader *header;
SHMCBIndex *idx = NULL;
unsigned int gap, new_pos, loop, new_offset;
int need;
ssl_log(s, SSL_LOG_TRACE, "entering shmcb_insert_encoded_session, "
"*queue->pos_count = %u", shmcb_get_safe_uint(queue->pos_count));
/* If there's entries to expire, ditch them first thing. */
shmcb_expire_division(s, queue, cache);
header = cache->header;
gap = header->cache_data_size - shmcb_get_safe_uint(cache->pos_count);
if (gap < encoded_len) {
new_pos = shmcb_get_safe_uint(queue->first_pos);
loop = 0;
need = (int) encoded_len - (int) gap;
while ((need > 0) && (loop + 1 < shmcb_get_safe_uint(queue->pos_count))) {
new_pos = shmcb_cyclic_increment(header->index_num, new_pos, 1);
loop += 1;
idx = shmcb_get_index(queue, new_pos);
need = (int) encoded_len - (int) gap -
shmcb_cyclic_space(header->cache_data_size,
shmcb_get_safe_uint(cache->first_pos),
shmcb_get_safe_uint(&(idx->offset)));
}
if (loop > 0) {
ssl_log(s, SSL_LOG_TRACE, "about to scroll %u sessions from %u",
loop, shmcb_get_safe_uint(queue->pos_count));
/* We are removing "loop" items from the cache. */
shmcb_set_safe_uint(cache->pos_count,
shmcb_get_safe_uint(cache->pos_count) -
shmcb_cyclic_space(header->cache_data_size,
shmcb_get_safe_uint(cache->first_pos),
shmcb_get_safe_uint(&(idx->offset))));
shmcb_set_safe_uint(cache->first_pos, shmcb_get_safe_uint(&(idx->offset)));
shmcb_set_safe_uint(queue->pos_count, shmcb_get_safe_uint(queue->pos_count) - loop);
shmcb_set_safe_uint(queue->first_pos, new_pos);
ssl_log(s, SSL_LOG_TRACE, "now only have %u sessions",
shmcb_get_safe_uint(queue->pos_count));
/* Update the stats!!! */
header->num_scrolled += loop;
}
}
/* probably unecessary checks, but I'll leave them until this code
* is verified. */
if (shmcb_get_safe_uint(cache->pos_count) + encoded_len >
header->cache_data_size) {
ssl_log(s, SSL_LOG_ERROR, "shmcb_insert_encoded_session, "
"internal error");
return FALSE;
}
if (shmcb_get_safe_uint(queue->pos_count) == header->index_num) {
ssl_log(s, SSL_LOG_ERROR, "shmcb_insert_encoded_session, "
"internal error");
return FALSE;
}
ssl_log(s, SSL_LOG_TRACE, "we have %u bytes and %u indexes free - "
"enough", header->cache_data_size -
shmcb_get_safe_uint(cache->pos_count), header->index_num -
shmcb_get_safe_uint(queue->pos_count));
/* HERE WE ASSUME THAT THE NEW SESSION SHOULD GO ON THE END! I'M NOT
* CHECKING WHETHER IT SHOULD BE GENUINELY "INSERTED" SOMEWHERE.
*
* We either fix that, or find out at a "higher" (read "mod_ssl")
* level whether it is possible to have distinct session caches for
* any attempted tomfoolery to do with different session timeouts.
* Knowing in advance that we can have a cache-wide constant timeout
* would make this stuff *MUCH* more efficient. Mind you, it's very
* efficient right now because I'm ignoring this problem!!!
*/
/* Increment to the first unused byte */
new_offset = shmcb_cyclic_increment(header->cache_data_size,
shmcb_get_safe_uint(cache->first_pos),
shmcb_get_safe_uint(cache->pos_count));
/* Copy the DER-encoded session into place */
shmcb_cyclic_ntoc_memcpy(header->cache_data_size, cache->data,
new_offset, encoded, encoded_len);
/* Get the new index that this session is stored in. */
new_pos = shmcb_cyclic_increment(header->index_num,
shmcb_get_safe_uint(queue->first_pos),
shmcb_get_safe_uint(queue->pos_count));
ssl_log(s, SSL_LOG_TRACE, "storing in index %u, at offset %u", new_pos,
new_offset);
idx = shmcb_get_index(queue, new_pos);
if (idx == NULL) {
ssl_log(s, SSL_LOG_ERROR, "shmcb_insert_encoded_session, "
"internal error");
return FALSE;
}
memset(idx, 0, sizeof(SHMCBIndex));
shmcb_set_safe_time(&(idx->expires), expiry_time);
shmcb_set_safe_uint(&(idx->offset), new_offset);
/* idx->removed = (unsigned char)0; */ /* Not needed given the memset above. */
idx->s_id2 = session_id[1];
ssl_log(s, SSL_LOG_TRACE, "session_id[0]=%u, idx->s_id2=%u",
session_id[0], session_id[1]);
/* All that remains is to adjust the cache's and queue's "pos_count"s. */
shmcb_set_safe_uint(cache->pos_count,
shmcb_get_safe_uint(cache->pos_count) + encoded_len);
shmcb_set_safe_uint(queue->pos_count,
shmcb_get_safe_uint(queue->pos_count) + 1);
/* And just for good debugging measure ... */
ssl_log(s, SSL_LOG_TRACE, "leaving now with %u bytes in the cache and "
"%u indexes", shmcb_get_safe_uint(cache->pos_count),
shmcb_get_safe_uint(queue->pos_count));
ssl_log(s, SSL_LOG_TRACE, "leaving shmcb_insert_encoded_session");
return TRUE;
}
/* Performs a lookup into a queue/cache pair for a
* session_id. If found, the session is deserialised
* and returned, otherwise NULL. */
static SSL_SESSION *shmcb_lookup_session_id(
server_rec *s, SHMCBQueue *queue,
SHMCBCache *cache, UCHAR *id,
int idlen)
{
unsigned char tempasn[SSL_SESSION_MAX_DER];
SHMCBIndex *idx;
SHMCBHeader *header;
SSL_SESSION *pSession = NULL;
unsigned int curr_pos, loop, count;
unsigned char *ptr;
time_t now;
ssl_log(s, SSL_LOG_TRACE, "entering shmcb_lookup_session_id");
/* If there are entries to expire, ditch them first thing. */
shmcb_expire_division(s, queue, cache);
now = time(NULL);
curr_pos = shmcb_get_safe_uint(queue->first_pos);
count = shmcb_get_safe_uint(queue->pos_count);
header = queue->header;
for (loop = 0; loop < count; loop++) {
ssl_log(s, SSL_LOG_TRACE, "loop=%u, count=%u, curr_pos=%u",
loop, count, curr_pos);
idx = shmcb_get_index(queue, curr_pos);
ssl_log(s, SSL_LOG_TRACE, "idx->s_id2=%u, id[1]=%u, offset=%u",
idx->s_id2, id[1], shmcb_get_safe_uint(&(idx->offset)));
/* Only look into the session further if;
* (a) the second byte of the session_id matches,
* (b) the "removed" flag isn't set,
* (c) the session hasn't expired yet.
* We do (c) like this so that it saves us having to
* do natural expiries ... naturally expired sessions
* scroll off the front anyway when the cache is full and
* "rotating", the only real issue that remains is the
* removal or disabling of forcibly killed sessions. */
if ((idx->s_id2 == id[1]) && !idx->removed &&
(shmcb_get_safe_time(&(idx->expires)) > now)) {
ssl_log(s, SSL_LOG_TRACE, "at index %u, found possible "
"session match", curr_pos);
shmcb_cyclic_cton_memcpy(header->cache_data_size,
tempasn, cache->data,
shmcb_get_safe_uint(&(idx->offset)),
SSL_SESSION_MAX_DER);
ptr = tempasn;
pSession = d2i_SSL_SESSION(NULL, &ptr, SSL_SESSION_MAX_DER);
if (pSession == NULL) {
ssl_log(s, SSL_LOG_ERROR, "scach2_lookup_"
"session_id, internal error");
return NULL;
}
if ((pSession->session_id_length == idlen) &&
(memcmp(pSession->session_id, id, idlen) == 0)) {
ssl_log(s, SSL_LOG_TRACE, "a match!");
return pSession;
}
ssl_log(s, SSL_LOG_TRACE, "not a match");
SSL_SESSION_free(pSession);
pSession = NULL;
}
curr_pos = shmcb_cyclic_increment(header->index_num, curr_pos, 1);
}
ssl_log(s, SSL_LOG_TRACE, "no matching sessions were found");
return NULL;
}
static BOOL shmcb_remove_session_id(
server_rec *s, SHMCBQueue *queue,
SHMCBCache *cache, UCHAR *id, int idlen)
{
unsigned char tempasn[SSL_SESSION_MAX_DER];
SSL_SESSION *pSession = NULL;
SHMCBIndex *idx;
SHMCBHeader *header;
unsigned int curr_pos, loop, count;
unsigned char *ptr;
BOOL to_return = FALSE;
ssl_log(s, SSL_LOG_TRACE, "entering shmcb_remove_session_id");
/* If there's entries to expire, ditch them first thing. */
/* shmcb_expire_division(s, queue, cache); */
/* Regarding the above ... hmmm ... I know my expiry code is slightly
* "faster" than all this remove stuff ... but if the higher level
* code calls a "remove" operation (and this *only* seems to happen
* when it has spotted an expired session before we had a chance to)
* then it should get credit for a remove (stats-wise). Also, in the
* off-chance that the server *requests* a renegotiate and wants to
* wipe the session clean we should give that priority over our own
* routine expiry handling. So I've moved the expiry check to *after*
* this general remove stuff. */
curr_pos = shmcb_get_safe_uint(queue->first_pos);
count = shmcb_get_safe_uint(queue->pos_count);
header = cache->header;
for (loop = 0; loop < count; loop++) {
ssl_log(s, SSL_LOG_TRACE, "loop=%u, count=%u, curr_pos=%u",
loop, count, curr_pos);
idx = shmcb_get_index(queue, curr_pos);
ssl_log(s, SSL_LOG_TRACE, "idx->s_id2=%u, id[1]=%u", idx->s_id2,
id[1]);
/* Only look into the session further if the second byte of the
* session_id matches. */
if (idx->s_id2 == id[1]) {
ssl_log(s, SSL_LOG_TRACE, "at index %u, found possible "
"session match", curr_pos);
shmcb_cyclic_cton_memcpy(header->cache_data_size,
tempasn, cache->data,
shmcb_get_safe_uint(&(idx->offset)),
SSL_SESSION_MAX_DER);
ptr = tempasn;
pSession = d2i_SSL_SESSION(NULL, &ptr, SSL_SESSION_MAX_DER);
if (pSession == NULL) {
ssl_log(s, SSL_LOG_ERROR, "shmcb_remove_session_id, "
"internal error");
goto end;
}
if ((pSession->session_id_length == idlen)
&& (memcmp(id, pSession->session_id, idlen) == 0)) {
ssl_log(s, SSL_LOG_TRACE, "a match!");
/* Scrub out this session "quietly" */
idx->removed = (unsigned char) 1;
SSL_SESSION_free(pSession);
to_return = TRUE;
goto end;
}
ssl_log(s, SSL_LOG_TRACE, "not a match");
SSL_SESSION_free(pSession);
pSession = NULL;
}
curr_pos = shmcb_cyclic_increment(header->index_num, curr_pos, 1);
}
ssl_log(s, SSL_LOG_TRACE, "no matching sessions were found");
/* If there's entries to expire, ditch them now. */
shmcb_expire_division(s, queue, cache);
end:
ssl_log(s, SSL_LOG_TRACE, "leaving shmcb_remove_session_id");
return to_return;
}