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freebsd/sys/netinet/accf_http.c
Alfred Perlstein 34b94e8b82 Accept filter maintainance 
Update copyrights.

Introduce a new sysctl node:
  net.inet.accf

Although acceptfilters need refcounting to be properly (safely) unloaded
as a temporary hack allow them to be unloaded if the sysctl
net.inet.accf.unloadable is set, this is really for developers who want
to work on thier own filters.

A near complete re-write of the accf_http filter:
  1) Parse check if the request is HTTP/1.0 or HTTP/1.1 if not dump
     to the application.
     Because of the performance implications of this there is a sysctl
     'net.inet.accf.http.parsehttpversion' that when set to non-zero
     parses the HTTP version.
     The default is to parse the version.
  2) Check if a socket has filled and dump to the listener
  3) optimize the way that mbuf boundries are handled using some voodoo
  4) even though you'd expect accept filters to only be used on TCP
     connections that don't use m_nextpkt I've fixed the accept filter
     for socket connections that use this.

This rewrite of accf_http should allow someone to use them and maintain
full HTTP compliance as long as net.inet.accf.http.parsehttpversion is
set.
2000-09-06 18:49:13 +00:00

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/*
* Copyright (c) 2000 Paycounter, Inc.
* Author: Alfred Perlstein <alfred@paycounter.com>, <alfred@FreeBSD.org>
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS 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 THE AUTHOR OR 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.
*
* $FreeBSD$
*/
#define ACCEPT_FILTER_MOD
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <sys/unistd.h>
#include <sys/file.h>
#include <sys/fcntl.h>
#include <sys/protosw.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/stat.h>
#include <sys/mbuf.h>
#include <sys/resource.h>
#include <sys/sysent.h>
#include <sys/resourcevar.h>
/* check for GET/HEAD */
static void sohashttpget(struct socket *so, void *arg, int waitflag);
/* check for HTTP/1.0 or HTTP/1.1 */
static void soparsehttpvers(struct socket *so, void *arg, int waitflag);
/* check for end of HTTP/1.x request */
static void soishttpconnected(struct socket *so, void *arg, int waitflag);
/* strcmp on an mbuf chain */
static int mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp);
/* strncmp on an mbuf chain */
static int mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset,
int max, char *cmp);
/* socketbuffer is full */
static int sbfull(struct sockbuf *sb);
static struct accept_filter accf_http_filter = {
"httpready",
sohashttpget,
NULL,
NULL
};
static moduledata_t accf_http_mod = {
"accf_http",
accept_filt_generic_mod_event,
&accf_http_filter
};
DECLARE_MODULE(accf_http, accf_http_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE);
static int parse_http_version = 1;
SYSCTL_NODE(_net_inet_accf, OID_AUTO, http, CTLFLAG_RW, 0,
"HTTP accept filter");
SYSCTL_INT(_net_inet_accf_http, OID_AUTO, parsehttpversion, CTLFLAG_RW,
&parse_http_version, 1,
"Parse http version so that non 1.x requests work");
#ifdef ACCF_HTTP_DEBUG
#define DPRINT(fmt, args...) \
do { \
printf("%s:%d: " fmt "\n", __func__, __LINE__ , ##args); \
} while (0)
#else
#define DPRINT(fmt, args...)
#endif
static int
sbfull(struct sockbuf *sb)
{
DPRINT("sbfull, cc(%ld) >= hiwat(%ld): %d, mbcnt(%ld) >= mbmax(%ld): %d",
sb->sb_cc, sb->sb_hiwat, sb->sb_cc >= sb->sb_hiwat,
sb->sb_mbcnt, sb->sb_mbmax, sb->sb_mbcnt >= sb->sb_mbmax);
return(sb->sb_cc >= sb->sb_hiwat || sb->sb_mbcnt >= sb->sb_mbmax);
}
/*
* start at mbuf m, (must provide npkt if exists)
* starting at offset in m compare characters in mbuf chain for 'cmp'
*/
static int
mbufstrcmp(struct mbuf *m, struct mbuf *npkt, int offset, char *cmp)
{
struct mbuf *n;
for (;m != NULL; m = n) {
n = npkt;
if (npkt)
npkt = npkt->m_nextpkt;
for (; m; m = m->m_next) {
for (; offset < m->m_len; offset++, cmp++) {
if (*cmp == '\0') {
return (1);
} else if (*cmp != *(mtod(m, char *) + offset)) {
return (0);
}
}
offset = 0;
}
}
return (0);
}
/*
* start at mbuf m, (must provide npkt if exists)
* starting at offset in m compare characters in mbuf chain for 'cmp'
* stop at 'max' characters
*/
static int
mbufstrncmp(struct mbuf *m, struct mbuf *npkt, int offset, int max, char *cmp)
{
struct mbuf *n;
for (;m != NULL; m = n) {
n = npkt;
if (npkt)
npkt = npkt->m_nextpkt;
for (; m; m = m->m_next) {
for (; offset < m->m_len; offset++, cmp++, max--) {
if (max == 0 || *cmp == '\0') {
return (1);
} else if (*cmp != *(mtod(m, char *) + offset)) {
return (0);
}
}
offset = 0;
}
}
return (0);
}
#define STRSETUP(sptr, slen, str) \
do { \
sptr = str; \
slen = sizeof(str) - 1; \
} while(0)
static void
sohashttpget(struct socket *so, void *arg, int waitflag)
{
if ((so->so_state & SS_CANTRCVMORE) == 0 || !sbfull(&so->so_rcv)) {
struct mbuf *m;
char *cmp;
int cmplen, cc;
m = so->so_rcv.sb_mb;
cc = so->so_rcv.sb_cc - 1;
if (cc < 1)
return;
switch (*mtod(m, char *)) {
case 'G':
STRSETUP(cmp, cmplen, "ET ");
break;
case 'H':
STRSETUP(cmp, cmplen, "EAD ");
break;
default:
goto fallout;
}
if (cc < cmplen) {
if (mbufstrncmp(m, m->m_nextpkt, 1, cc, cmp) == 1) {
DPRINT("short cc (%d) but mbufstrncmp ok", cc);
return;
} else {
DPRINT("short cc (%d) mbufstrncmp failed", cc);
goto fallout;
}
}
if (mbufstrcmp(m, m->m_nextpkt, 1, cmp) == 1) {
DPRINT("mbufstrcmp ok");
if (parse_http_version == 0)
soishttpconnected(so, arg, waitflag);
else
soparsehttpvers(so, arg, waitflag);
return;
}
DPRINT("mbufstrcmp bad");
}
fallout:
DPRINT("fallout");
so->so_upcall = NULL;
so->so_rcv.sb_flags &= ~SB_UPCALL;
soisconnected(so);
return;
}
static void
soparsehttpvers(struct socket *so, void *arg, int waitflag)
{
struct mbuf *m, *n;
int i, cc, spaces, inspaces;
if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
goto fallout;
m = so->so_rcv.sb_mb;
cc = so->so_rcv.sb_cc;
inspaces = spaces = 0;
for (m = so->so_rcv.sb_mb; m; m = n) {
n = m->m_nextpkt;
for (; m; m = m->m_next) {
for (i = 0; i < m->m_len; i++, cc--) {
switch (*(mtod(m, char *) + i)) {
case ' ':
if (!inspaces) {
spaces++;
inspaces = 1;
}
break;
case '\r':
case '\n':
DPRINT("newline");
goto fallout;
default:
if (spaces == 2) {
/* make sure we have enough data left */
if (cc < sizeof("HTTP/1.0") - 1) {
if (mbufstrncmp(m, n, i, cc, "HTTP/1.") == 1) {
DPRINT("mbufstrncmp ok");
goto readmore;
} else {
DPRINT("mbufstrncmp bad");
goto fallout;
}
} else if (mbufstrcmp(m, n, i, "HTTP/1.0") == 1 ||
mbufstrcmp(m, n, i, "HTTP/1.1") == 1) {
DPRINT("mbufstrcmp ok");
soishttpconnected(so, arg, waitflag);
return;
} else {
DPRINT("mbufstrcmp bad");
goto fallout;
}
}
inspaces = 0;
break;
}
}
}
}
readmore:
DPRINT("readmore");
/*
* if we hit here we haven't hit something
* we don't understand or a newline, so try again
*/
so->so_upcall = soparsehttpvers;
so->so_rcv.sb_flags |= SB_UPCALL;
return;
fallout:
DPRINT("fallout");
so->so_upcall = NULL;
so->so_rcv.sb_flags &= ~SB_UPCALL;
soisconnected(so);
return;
}
#define NCHRS 3
static void
soishttpconnected(struct socket *so, void *arg, int waitflag)
{
char a, b, c;
struct mbuf *m, *n;
int ccleft, copied;
DPRINT("start");
if ((so->so_state & SS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
goto gotit;
/*
* Walk the socketbuffer and copy the last NCHRS (3) into a, b, and c
* copied - how much we've copied so far
* ccleft - how many bytes remaining in the socketbuffer
* just loop over the mbufs subtracting from 'ccleft' until we only
* have NCHRS left
*/
copied = 0;
ccleft = so->so_rcv.sb_cc;
if (ccleft < NCHRS)
goto readmore;
a = b = c = '\0';
for (m = so->so_rcv.sb_mb; m; m = n) {
n = m->m_nextpkt;
for (; m; m = m->m_next) {
ccleft -= m->m_len;
if (ccleft <= NCHRS) {
char *src;
int tocopy;
tocopy = (NCHRS - ccleft) - copied;
src = mtod(m, char *) + (m->m_len - tocopy);
while (tocopy--) {
switch (copied++) {
case 0:
a = *src++;
break;
case 1:
b = *src++;
break;
case 2:
c = *src++;
break;
}
}
}
}
}
if (c == '\n' && (b == '\n' || (b == '\r' && a == '\n'))) {
/* we have all request headers */
goto gotit;
}
readmore:
so->so_upcall = soishttpconnected;
so->so_rcv.sb_flags |= SB_UPCALL;
return;
gotit:
so->so_upcall = NULL;
so->so_rcv.sb_flags &= ~SB_UPCALL;
soisconnected(so);
return;
}
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