HardenedBSD/lib/libpcap/pcap-netmap.c
Luigi Rizzo 86f82ef946 Add netmap support to libpcap. Tcpdump and other native pcap application can now
run directly on netmap ports using netmap:foo or valeXX:YY device names.
Modifications to existing code are small and trivial, the netmap-specific
code is all in a new file.

Please be aware that in netmap mode the physical interface is disconnected from
the host stack, so libpcap will steal the traffic not just make a copy.

For the full version of the code (including linux and autotools support) see
	https://code.google.com/p/netmap-libpcap/

MFC after:	3 days
2014-10-06 15:48:28 +00:00

284 lines
6.9 KiB
C

/*
* Copyright (C) 2014 Luigi Rizzo. 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <poll.h>
#include <ctype.h>
#include <errno.h>
#include <netdb.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define NETMAP_WITH_LIBS
#include <net/netmap_user.h>
#include "pcap-int.h"
/*
* $FreeBSD$
*
* This code is meant to build also on other versions of libpcap.
*
* older libpcap miss p->priv, use p->md.device instead (and allocate).
* Also opt.timeout was in md.timeout before.
* Use #define PCAP_IF_UP to discriminate
*/
#ifdef PCAP_IF_UP
#define NM_PRIV(p) ((struct pcap_netmap *)(p->priv))
#define the_timeout opt.timeout
#else
#define HAVE_NO_PRIV
#define NM_PRIV(p) ((struct pcap_netmap *)(p->md.device))
#define SET_PRIV(p, x) p->md.device = (void *)x
#define the_timeout md.timeout
#endif
#if defined (linux)
/* On FreeBSD we use IFF_PPROMISC which is in ifr_flagshigh.
* remap to IFF_PROMISC on linux
*/
#define IFF_PPROMISC IFF_PROMISC
#endif /* linux */
struct pcap_netmap {
struct nm_desc *d; /* pointer returned by nm_open() */
pcap_handler cb; /* callback and argument */
u_char *cb_arg;
int must_clear_promisc; /* flag */
uint64_t rx_pkts; /* # of pkts received before the filter */
};
static int
pcap_netmap_stats(pcap_t *p, struct pcap_stat *ps)
{
struct pcap_netmap *pn = NM_PRIV(p);
ps->ps_recv = pn->rx_pkts;
ps->ps_drop = 0;
ps->ps_ifdrop = 0;
return 0;
}
static void
pcap_netmap_filter(u_char *arg, struct pcap_pkthdr *h, const u_char *buf)
{
pcap_t *p = (pcap_t *)arg;
struct pcap_netmap *pn = NM_PRIV(p);
const struct bpf_insn *pc = p->fcode.bf_insns;
++pn->rx_pkts;
if (pc == NULL || bpf_filter(pc, buf, h->len, h->caplen))
pn->cb(pn->cb_arg, h, buf);
}
static int
pcap_netmap_dispatch(pcap_t *p, int cnt, pcap_handler cb, u_char *user)
{
int ret;
struct pcap_netmap *pn = NM_PRIV(p);
struct nm_desc *d = pn->d;
struct pollfd pfd = { .fd = p->fd, .events = POLLIN, .revents = 0 };
pn->cb = cb;
pn->cb_arg = user;
for (;;) {
if (p->break_loop) {
p->break_loop = 0;
return PCAP_ERROR_BREAK;
}
/* nm_dispatch won't run forever */
ret = nm_dispatch((void *)d, cnt, (void *)pcap_netmap_filter, (void *)p);
if (ret != 0)
break;
errno = 0;
ret = poll(&pfd, 1, p->the_timeout);
}
return ret;
}
/* XXX need to check the NIOCTXSYNC/poll */
static int
pcap_netmap_inject(pcap_t *p, const void *buf, size_t size)
{
struct nm_desc *d = NM_PRIV(p)->d;
return nm_inject(d, buf, size);
}
static int
pcap_netmap_ioctl(pcap_t *p, u_long what, uint32_t *if_flags)
{
struct pcap_netmap *pn = NM_PRIV(p);
struct nm_desc *d = pn->d;
struct ifreq ifr;
int error, fd = d->fd;
#ifdef linux
fd = socket(AF_INET, SOCK_DGRAM, 0);
if (fd < 0) {
fprintf(stderr, "Error: cannot get device control socket.\n");
return -1;
}
#endif /* linux */
bzero(&ifr, sizeof(ifr));
strncpy(ifr.ifr_name, d->req.nr_name, sizeof(ifr.ifr_name));
switch (what) {
case SIOCSIFFLAGS:
ifr.ifr_flags = *if_flags;
#ifdef __FreeBSD__
ifr.ifr_flagshigh = *if_flags >> 16;
#endif /* __FreeBSD__ */
break;
}
error = ioctl(fd, what, &ifr);
if (!error) {
switch (what) {
case SIOCGIFFLAGS:
*if_flags = ifr.ifr_flags;
#ifdef __FreeBSD__
*if_flags |= (ifr.ifr_flagshigh << 16);
#endif /* __FreeBSD__ */
}
}
#ifdef linux
close(fd);
#endif /* linux */
return error ? -1 : 0;
}
static void
pcap_netmap_close(pcap_t *p)
{
struct pcap_netmap *pn = NM_PRIV(p);
struct nm_desc *d = pn->d;
uint32_t if_flags = 0;
if (pn->must_clear_promisc) {
pcap_netmap_ioctl(p, SIOCGIFFLAGS, &if_flags); /* fetch flags */
if (if_flags & IFF_PPROMISC) {
if_flags &= ~IFF_PPROMISC;
pcap_netmap_ioctl(p, SIOCSIFFLAGS, &if_flags);
}
}
nm_close(d);
#ifdef HAVE_NO_PRIV
free(pn);
SET_PRIV(p, NULL); // unnecessary
#endif
pcap_cleanup_live_common(p);
}
static int
pcap_netmap_activate(pcap_t *p)
{
struct pcap_netmap *pn = NM_PRIV(p);
struct nm_desc *d = nm_open(p->opt.source, NULL, 0, NULL);
uint32_t if_flags = 0;
if (d == NULL) {
snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
"netmap open: cannot access %s: %s\n",
p->opt.source, pcap_strerror(errno));
#ifdef HAVE_NO_PRIV
free(pn);
SET_PRIV(p, NULL); // unnecessary
#endif
pcap_cleanup_live_common(p);
return (PCAP_ERROR);
}
if (0)
fprintf(stderr, "%s device %s priv %p fd %d ports %d..%d\n",
__FUNCTION__, p->opt.source, d, d->fd,
d->first_rx_ring, d->last_rx_ring);
pn->d = d;
p->fd = d->fd;
if (p->opt.promisc && !(d->req.nr_ringid & NETMAP_SW_RING)) {
pcap_netmap_ioctl(p, SIOCGIFFLAGS, &if_flags); /* fetch flags */
if (!(if_flags & IFF_PPROMISC)) {
pn->must_clear_promisc = 1;
if_flags |= IFF_PPROMISC;
pcap_netmap_ioctl(p, SIOCSIFFLAGS, &if_flags);
}
}
p->linktype = DLT_EN10MB;
p->selectable_fd = p->fd;
p->read_op = pcap_netmap_dispatch;
p->inject_op = pcap_netmap_inject,
p->setfilter_op = install_bpf_program;
p->setdirection_op = NULL;
p->set_datalink_op = NULL;
p->getnonblock_op = pcap_getnonblock_fd;
p->setnonblock_op = pcap_setnonblock_fd;
p->stats_op = pcap_netmap_stats;
p->cleanup_op = pcap_netmap_close;
return (0);
}
pcap_t *
pcap_netmap_create(const char *device, char *ebuf, int *is_ours)
{
pcap_t *p;
*is_ours = (!strncmp(device, "netmap:", 7) || !strncmp(device, "vale", 4));
if (! *is_ours)
return NULL;
#ifdef HAVE_NO_PRIV
{
void *pn = calloc(1, sizeof(struct pcap_netmap));
if (pn == NULL)
return NULL;
p = pcap_create_common(device, ebuf);
if (p == NULL) {
free(pn);
return NULL;
}
SET_PRIV(p, pn);
}
#else
p = pcap_create_common(device, ebuf, sizeof (struct pcap_netmap));
if (p == NULL)
return (NULL);
#endif
p->activate_op = pcap_netmap_activate;
return (p);
}