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-rw-r--r--pcap-pf.c35
1 files changed, 32 insertions, 3 deletions
diff --git a/pcap-pf.c b/pcap-pf.c
index 3fa1c84..3a59083 100644
--- a/pcap-pf.c
+++ b/pcap-pf.c
@@ -24,7 +24,7 @@
#ifndef lint
static const char rcsid[] _U_ =
- "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.86 2004-02-09 06:24:42 guy Exp $ (LBL)";
+ "@(#) $Header: /tcpdump/master/libpcap/pcap-pf.c,v 1.87 2004-03-23 19:18:06 guy Exp $ (LBL)";
#endif
#ifdef HAVE_CONFIG_H
@@ -220,6 +220,20 @@ pcap_read_pf(pcap_t *pc, int cnt, pcap_handler callback, u_char *user)
}
static int
+pcap_inject_pf(pcap_t *p, const void *buf, size_t size)
+{
+ int ret;
+
+ ret = write(p->fd, buf, size);
+ if (ret == -1) {
+ snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s",
+ pcap_strerror(errno));
+ return (-1);
+ }
+ return (ret);
+}
+
+static int
pcap_stats_pf(pcap_t *p, struct pcap_stat *ps)
{
@@ -299,14 +313,28 @@ pcap_open_live(const char *device, int snaplen, int promisc, int to_ms,
return (0);
}
memset(p, 0, sizeof(*p));
-
/*
+ * Initially try a read/write open (to allow the inject
+ * method to work). If that fails due to permission
+ * issues, fall back to read-only. This allows a
+ * non-root user to be granted specific access to pcap
+ * capabilities via file permissions.
+ *
+ * XXX - we should have an API that has a flag that
+ * controls whether to open read-only or read-write,
+ * so that denial of permission to send (or inability
+ * to send, if sending packets isn't supported on
+ * the device in question) can be indicated at open
+ * time.
+ *
* XXX - we assume here that "pfopen()" does not, in fact, modify
* its argument, even though it takes a "char *" rather than a
* "const char *" as its first argument. That appears to be
* the case, at least on Digital UNIX 4.0.
*/
- p->fd = pfopen(device, O_RDONLY);
+ p->fd = pfopen(device, O_RDWR);
+ if (p->fd == -1 && errno == EACCES)
+ p->fd = pfopen(device, O_RDONLY);
if (p->fd < 0) {
snprintf(ebuf, PCAP_ERRBUF_SIZE, "pf open: %s: %s\n\
your system may not be properly configured; see the packetfilter(4) man page\n",
@@ -467,6 +495,7 @@ your system may not be properly configured; see the packetfilter(4) man page\n",
p->selectable_fd = p->fd;
p->read_op = pcap_read_pf;
+ p->inject_op = pcap_inject_pf;
p->setfilter_op = pcap_setfilter_pf;
p->set_datalink_op = NULL; /* can't change data link type */
p->getnonblock_op = pcap_getnonblock_fd;