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inpcb: immediately return matching pcb on lookup

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This saves a lot of CPU cycles if you got large connection table.

The code removed originates from 413628a7e3, a very large changeset.
Discussed that with Bjoern, Jamie we can't recover why would we ever
have identical 4-tuples in the hash, even in the presence of jails.
Bjoern did a test that confirms that it is impossible to allocate an
identical connection from a jail to a host. Code review also confirms
that system shouldn't allow for such connections to exist.

With a lack of proper test suite we decided to take a risk and go
forward with removing that code.

Reviewed by:		gallatin, bz, markj
Differential Revision:	https://reviews.freebsd.org/D38015
This commit is contained in:
Gleb Smirnoff 2023-02-07 09:21:52 -08:00
parent dfc4d218ce
commit 220d892129
2 changed files with 6 additions and 30 deletions
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18
sys/netinet/in_pcb.c
View File

@ -2225,7 +2225,7 @@ in_pcblookup_hash_locked(struct inpcbinfo *pcbinfo, struct in_addr faddr,
struct ifnet *ifp, uint8_t numa_domain)
{
struct inpcbhead *head;
struct inpcb *inp, *tmpinp;
struct inpcb *inp;
u_short fport = fport_arg, lport = lport_arg;
KASSERT((lookupflags & ~(INPLOOKUP_WILDCARD)) == 0,
@ -2239,7 +2239,6 @@ in_pcblookup_hash_locked(struct inpcbinfo *pcbinfo, struct in_addr faddr,
/*
* First look for an exact match.
*/
tmpinp = NULL;
head = &pcbinfo->ipi_hashbase[INP_PCBHASH(&faddr, lport, fport,
pcbinfo->ipi_hashmask)];
CK_LIST_FOREACH(inp, head, inp_hash) {
@ -2251,20 +2250,9 @@ in_pcblookup_hash_locked(struct inpcbinfo *pcbinfo, struct in_addr faddr,
if (inp->inp_faddr.s_addr == faddr.s_addr &&
inp->inp_laddr.s_addr == laddr.s_addr &&
inp->inp_fport == fport &&
inp->inp_lport == lport) {
/*
* XXX We should be able to directly return
* the inp here, without any checks.
* Well unless both bound with SO_REUSEPORT?
*/
if (prison_flag(inp->inp_cred, PR_IP4))
return (inp);
if (tmpinp == NULL)
tmpinp = inp;
}
inp->inp_lport == lport)
return (inp);
}
if (tmpinp != NULL)
return (tmpinp);
/*
* Then look for a wildcard match, if requested.

18
sys/netinet6/in6_pcb.c
View File

@ -966,7 +966,7 @@ in6_pcblookup_hash_locked(struct inpcbinfo *pcbinfo, struct in6_addr *faddr,
int lookupflags, struct ifnet *ifp, uint8_t numa_domain)
{
struct inpcbhead *head;
struct inpcb *inp, *tmpinp;
struct inpcb *inp;
u_short fport = fport_arg, lport = lport_arg;
KASSERT((lookupflags & ~(INPLOOKUP_WILDCARD)) == 0,
@ -981,7 +981,6 @@ in6_pcblookup_hash_locked(struct inpcbinfo *pcbinfo, struct in6_addr *faddr,
/*
* First look for an exact match.
*/
tmpinp = NULL;
head = &pcbinfo->ipi_hashbase[INP6_PCBHASH(faddr, lport, fport,
pcbinfo->ipi_hashmask)];
CK_LIST_FOREACH(inp, head, inp_hash) {
@ -991,20 +990,9 @@ in6_pcblookup_hash_locked(struct inpcbinfo *pcbinfo, struct in6_addr *faddr,
if (IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, faddr) &&
IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, laddr) &&
inp->inp_fport == fport &&
inp->inp_lport == lport) {
/*
* XXX We should be able to directly return
* the inp here, without any checks.
* Well unless both bound with SO_REUSEPORT?
*/
if (prison_flag(inp->inp_cred, PR_IP6))
return (inp);
if (tmpinp == NULL)
tmpinp = inp;
}
inp->inp_lport == lport)
return (inp);
}
if (tmpinp != NULL)
return (tmpinp);
/*
* Then look for a wildcard match, if requested.