/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#define ACCEPT_FILTER_MOD
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/mbuf.h>
#include <sys/module.h>
#include <sys/signalvar.h>
#include <sys/sysctl.h>
#include <sys/socketvar.h>
/* check for GET/HEAD */
static int sohashttpget(struct socket *so, void *arg, int waitflag);
/* check for HTTP/1.0 or HTTP/1.1 */
static int soparsehttpvers(struct socket *so, void *arg, int waitflag);
/* check for end of HTTP/1.x request */
static int 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;
static 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 (sbused(sb) >= 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);
}
if (*cmp == '\0')
return (1);
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);
}
if (max == 0 || *cmp == '\0')
return (1);
offset = 0;
}
}
return (0);
}
#define STRSETUP(sptr, slen, str) \
do { \
sptr = str; \
slen = sizeof(str) - 1; \
} while(0)
static int
sohashttpget(struct socket *so, void *arg, int waitflag)
{
if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) == 0 &&
!sbfull(&so->so_rcv)) {
struct mbuf *m;
char *cmp;
int cmplen, cc;
m = so->so_rcv.sb_mb;
cc = sbavail(&so->so_rcv) - 1;
if (cc < 1)
return (SU_OK);
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 (SU_OK);
} 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)
return (soishttpconnected(so, arg, waitflag));
else
return (soparsehttpvers(so, arg, waitflag));
}
DPRINT("mbufstrcmp bad");
}
fallout:
DPRINT("fallout");
return (SU_ISCONNECTED);
}
static int
soparsehttpvers(struct socket *so, void *arg, int waitflag)
{
struct mbuf *m, *n;
int i, cc, spaces, inspaces;
if ((so->so_rcv.sb_state & SBS_CANTRCVMORE) != 0 || sbfull(&so->so_rcv))
goto fallout;
m = so->so_rcv.sb_mb;
cc = sbavail(&so->so_rcv);
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 ' ':
/* tabs? '\t' */
if (!inspaces) {
spaces++;
inspaces = 1;
}
break;
case '\r':
case '\n':
DPRINT("newline");
goto fallout;
default:
if (spaces != 2) {
inspaces = 0;
break;
}
/*
* if we don't have enough characters
* left (cc < sizeof("HTTP/1.0") - 1)
* then see if the remaining ones
* are a request we can parse.
*/
if (cc < sizeof("HTTP/1.0") - 1) {
if (mbufstrncmp(m, n, i, cc,
"HTTP/1.") == 1) {
DPRINT("ok");
goto readmore;
} else {
DPRINT("bad");
goto fallout;
}
} else if (
mbufstrcmp(m, n, i, "HTTP/1.0") ||
mbufstrcmp(m, n, i, "HTTP/1.1")) {
DPRINT("ok");
return (soishttpconnected(so,
arg, waitflag));
} else {
DPRINT("bad");
goto fallout;
}
}
}
}
}
readmore:
DPRINT("readmore");
/*
* if we hit here we haven't hit something
* we don't understand or a newline, so try again
*/
soupcall_set(so, SO_RCV, soparsehttpvers, arg);
return (SU_OK);
fallout:
DPRINT("fallout");
return (SU_ISCONNECTED);
}
#define NCHRS 3
static int
soishttpconnected(struct socket *so, void *arg, int waitflag)
{
char a, b, c;
struct mbuf *m, *n;
int ccleft, copied;
DPRINT("start");
if ((so->so_rcv.sb_state & SBS_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 = sbavail(&so->so_rcv);
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:
soupcall_set(so, SO_RCV, soishttpconnected, arg);
return (SU_OK);
gotit:
return (SU_ISCONNECTED);
}