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Make session ID generator to use session ID hash.

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Make session ID generator thread-safe.
This commit is contained in:
Alexander Motin 2008-03-02 23:26:35 +00:00
parent 874f7ae331
commit bd500dab7f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=176753
1 changed files with 37 additions and 40 deletions
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77
sys/netgraph/ng_pppoe.c
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@ -281,43 +281,6 @@ static int pppoe_send_event(sessp sp, enum cmd cmdid);
* Author: Michal Ostrowski <mostrows@styx.uwaterloo.ca> *
************************************************************************/
/*
* Generate a new session id
* XXX find out the FreeBSD locking scheme.
*/
static uint16_t
get_new_sid(node_p node)
{
static int pppoe_sid = 10;
hook_p hook;
uint16_t val;
restart:
val = pppoe_sid++;
/*
* Spec says 0xFFFF is reserved.
* Also don't use 0x0000
*/
if (val == 0xffff) {
pppoe_sid = 20;
goto restart;
}
/* Check it isn't already in use. */
LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
sessp sp = NG_HOOK_PRIVATE(hook);
/* Skip any nonsession hook. */
if (sp == NULL)
continue;
if (sp->Session_ID == val)
goto restart;
}
CTR2(KTR_NET, "%20s: new sid %d", __func__, val);
return (val);
}
/*
@ -559,6 +522,42 @@ pppoe_find_svc(node_p node, const char *svc_name, int svc_len)
/**************************************************************************
* Routines to find a particular session that matches an incoming packet. *
**************************************************************************/
/* Find free session and add to hash. */
static uint16_t
pppoe_getnewsession(sessp sp)
{
const priv_p privp = NG_NODE_PRIVATE(NG_HOOK_NODE(sp->hook));
static uint16_t pppoe_sid = 1;
sessp tsp;
uint16_t val, hash;
restart:
/* Atomicity is not needed here as value will be checked. */
val = pppoe_sid++;
/* Spec says 0xFFFF is reserved, also don't use 0x0000. */
if (val == 0xffff || val == 0x0000)
val = pppoe_sid = 1;
/* Check it isn't already in use. */
hash = SESSHASH(val);
mtx_lock(&privp->sesshash[hash].mtx);
TAILQ_FOREACH(tsp, &privp->sesshash[hash].head, sessions) {
if (tsp->Session_ID == val)
break;
}
if (!tsp) {
sp->Session_ID = val;
TAILQ_INSERT_HEAD(&privp->sesshash[hash].head, sp, sessions);
}
mtx_unlock(&privp->sesshash[hash].mtx);
if (tsp)
goto restart;
CTR2(KTR_NET, "%20s: new sid %d", __func__, val);
return (val);
}
/* Add specified session to hash. */
static void
pppoe_addsession(sessp sp)
@ -1545,9 +1544,7 @@ ng_pppoe_rcvdata_ether(hook_p hook, item_p item)
neg->pkt->pkt_header.ph.code = PADS_CODE;
if (sp->Session_ID == 0) {
neg->pkt->pkt_header.ph.sid =
htons(sp->Session_ID
= get_new_sid(node));
pppoe_addsession(sp);
htons(pppoe_getnewsession(sp));
}
send_sessionid(sp);
neg->timeout = 0;