Add Myricom SNF API support as a new pcap device.

This patch adds support for our NICs when run in a specialized capture mode.
It is diffed against the current master.

The Myricom Sniffer10G software uses Myri-10G programmable Network Interface
Cards (NICs), a firmware extension, a specialized driver and a user-level
library (libsnf) to enable sustained capture of 10-Gigabit Ethernet traffic.
Small-packet coalescing and an efficient zero-copy path to host memory allow
Sniffer10G to capture streams at line rate for all Ethernet packet sizes.

Optionally, libpcap can be used concurrently by multiple processes on a single
NIC port to partition the incoming traffic across processes.  While the Linux
kernel enables this through multiple receive queues, the difference is that the
myri_snf driver cooperates with libsnf to set up multiple queues that are each
independently accessible through user-space.

More information here: http://www.myri.com/scs/SNF/doc

Signed-off-by: Guy Harris <guy@alum.mit.edu>

9 files changed, 675 insertions, 0 deletions

diff --git a/config.h.in b/config.h.in
index 990091d..55e13da 100644
--- a/config.h.in
+++ b/config.h.in
@@ -91,6 +91,9 @@
 /* define if you have a Septel API */
 #undef HAVE_SEPTEL_API
 
+/* define if you have Myricom SNF API */
+#undef HAVE_SNF_API
+
 /* Define to 1 if you have the `snprintf' function. */
 #undef HAVE_SNPRINTF
 
diff --git a/configure b/configure
index 961024d..dd86732 100755
--- a/configure
+++ b/configure
@@ -1313,6 +1313,11 @@ Optional Packages:
                           Endace DAG library directory
   --with-septel[=DIR]     include Septel support (located in directory DIR, if
                           supplied). [default=yes, on Linux, if present]
+  --with-snf[=DIR]        include Myricom SNF support ["yes", "no" or DIR;
+                          default="yes" on BSD and Linux if present]
+  --with-snf-includes=DIR Myricom SNF include directory
+  --with-snf-libraries=DIR
+                          Myricom SNF library directory
   --without-flex          don't use flex
   --without-bison         don't use bison
 
@@ -7800,6 +7805,10 @@ septel)
 	V_DEFS="$V_DEFS -DSEPTEL_ONLY"
 	;;
 
+snf)
+	V_DEFS="$V_DEFS -DSNF_ONLY"
+	;;
+
 null)
 	{ echo "$as_me:$LINENO: WARNING: cannot determine packet capture interface" >&5
 echo "$as_me: WARNING: cannot determine packet capture interface" >&2;}
@@ -9095,6 +9104,206 @@ echo "$as_me: error: Specifying the capture type as 'septel' requires the Septel
    { (exit 1); exit 1; }; }
 fi
 
+# Check for Myricom SNF support.
+
+# Check whether --with-snf was given.
+if test "${with_snf+set}" = set; then
+  withval=$with_snf;
+	if test "$withval" = no
+	then
+		# User explicitly doesn't want SNF
+		want_snf=no
+	elif test "$withval" = yes
+	then
+		# User wants SNF support but hasn't specific a directory.
+		want_snf=yes
+	else
+		# User wants SNF support with a specified directory.
+		want_snf=yes
+		snf_root=$withval
+	fi
+
+else
+
+	#
+	# Use Sniffer API if present, otherwise don't
+	#
+	want_snf=ifpresent
+
+fi
+
+
+
+# Check whether --with-snf-includes was given.
+if test "${with_snf_includes+set}" = set; then
+  withval=$with_snf_includes;
+	# User wants SNF with specific header directory
+	want_snf=yes
+	snf_include_dir=$withval
+
+fi
+
+
+
+# Check whether --with-snf-libraries was given.
+if test "${with_snf_libraries+set}" = set; then
+  withval=$with_snf_libraries;
+	# User wants SNF with specific lib directory
+	want_snf=yes
+	snf_lib_dir=$withval
+
+fi
+
+
+case "$V_PCAP" in
+bpf|linux|snf)
+	#
+	# We support the Sniffer API if we're on BSD, Linux, or if we're
+	# building a Sniffer-only libpcap.
+	#
+	;;
+*)
+	#
+	# If the user explicitly requested Sniffer, tell them it's not
+	# supported.
+	#
+	# If they expressed no preference, don't include it.
+	#
+	if test $want_snf = yes; then
+		{ { echo "$as_me:$LINENO: error: Myricom SNF support only available with 'bpf' 'linux' and 'snf' packet capture types" >&5
+echo "$as_me: error: Myricom SNF support only available with 'bpf' 'linux' and 'snf' packet capture types" >&2;}
+   { (exit 1); exit 1; }; }
+	elif test $want_snf = yes; then
+		want_snf=no
+	fi
+	;;
+esac
+
+ac_cv_lbl_snf_api=no
+if test "$with_snf" != no; then
+
+	{ echo "$as_me:$LINENO: checking whether we have Myricom Sniffer API" >&5
+echo $ECHO_N "checking whether we have Myricom Sniffer API... $ECHO_C" >&6; }
+
+	if test -z "$snf_root"; then
+		snf_root=/opt/snf
+	fi
+
+	if test -z "$snf_include_dir"; then
+		snf_include_dir="$snf_root/include"
+	fi
+
+	if test -z "$snf_lib_dir"; then
+		snf_lib_dir="$snf_root/lib"
+	fi
+
+	if test -f "$snf_include_dir/snf.h"; then
+		ac_cv_lbl_snf_api=yes
+	fi
+	{ echo "$as_me:$LINENO: result: $ac_cv_lbl_snf_api ($snf_root)" >&5
+echo "${ECHO_T}$ac_cv_lbl_snf_api ($snf_root)" >&6; }
+
+	if test $ac_cv_lbl_snf_api = no; then
+		if test "$want_snf" = yes; then
+			{ { echo "$as_me:$LINENO: error: SNF API headers not found under $snf_include_dir; use --without-snf" >&5
+echo "$as_me: error: SNF API headers not found under $snf_include_dir; use --without-snf" >&2;}
+   { (exit 1); exit 1; }; }
+		fi
+	else
+		saved_ldflags=$LDFLAGS
+		LDFLAGS="$LDFLAGS -L$snf_lib_dir"
+		{ echo "$as_me:$LINENO: checking for snf_init in -lsnf" >&5
+echo $ECHO_N "checking for snf_init in -lsnf... $ECHO_C" >&6; }
+if test "${ac_cv_lib_snf_snf_init+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lsnf  $LIBS"
+cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char snf_init ();
+int
+main ()
+{
+return snf_init ();
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_link") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest$ac_exeext &&
+       $as_test_x conftest$ac_exeext; then
+  ac_cv_lib_snf_snf_init=yes
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_cv_lib_snf_snf_init=no
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest_ipa8_conftest.oo \
+      conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ echo "$as_me:$LINENO: result: $ac_cv_lib_snf_snf_init" >&5
+echo "${ECHO_T}$ac_cv_lib_snf_snf_init" >&6; }
+if test $ac_cv_lib_snf_snf_init = yes; then
+  ac_cv_lbl_snf_api="yes"
+else
+  ac_cv_lbl_snf_api="no"
+fi
+
+		LDFLAGS="$saved_ldflags"
+
+		if test $ac_cv_lbl_snf_api = no; then
+			if test "$want_snf" = yes; then
+				{ { echo "$as_me:$LINENO: error: SNF API cannot correctly be linked check config.log; use --without-snf" >&5
+echo "$as_me: error: SNF API cannot correctly be linked check config.log; use --without-snf" >&2;}
+   { (exit 1); exit 1; }; }
+			fi
+		else
+			V_INCLS="$V_INCLS -I$snf_include_dir"
+			LIBS="$LIBS -L$snf_lib_dir -lsnf"
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_SNF_API 1
+_ACEOF
+
+		fi
+	fi
+fi
+
+if test "$V_PCAP" = snf -a "$ac_cv_lbl_snf_api" = no; then
+	{ { echo "$as_me:$LINENO: error: Specifying the capture type as 'snf' requires the Myricom Sniffer API to be present; use --with-snf=DIR" >&5
+echo "$as_me: error: Specifying the capture type as 'snf' requires the Myricom Sniffer API to be present; use --with-snf=DIR" >&2;}
+   { (exit 1); exit 1; }; }
+fi
 
 
 # Check whether --with-flex was given.
diff --git a/configure.in b/configure.in
index a0e5973..4e515cf 100644
--- a/configure.in
+++ b/configure.in
@@ -500,6 +500,10 @@ septel)
 	V_DEFS="$V_DEFS -DSEPTEL_ONLY"
 	;;
 
+snf)
+	V_DEFS="$V_DEFS -DSNF_ONLY"
+	;;
+
 null)
 	AC_MSG_WARN(cannot determine packet capture interface)
 	AC_MSG_WARN((see the INSTALL doc for more info))
@@ -978,6 +982,115 @@ if test "$V_PCAP" = septel -a "$ac_cv_lbl_septel_api" = no; then
 	AC_MSG_ERROR(Specifying the capture type as 'septel' requires the Septel API to be present; use --with-septel=DIR)
 fi
 
+# Check for Myricom SNF support.
+AC_ARG_WITH([snf],
+AC_HELP_STRING([--with-snf@<:@=DIR@:>@],[include Myricom SNF support @<:@"yes", "no" or DIR; default="yes" on BSD and Linux if present@:>@]),
+[
+	if test "$withval" = no
+	then
+		# User explicitly doesn't want SNF
+		want_snf=no
+	elif test "$withval" = yes
+	then
+		# User wants SNF support but hasn't specific a directory.
+		want_snf=yes
+	else
+		# User wants SNF support with a specified directory.
+		want_snf=yes
+		snf_root=$withval
+	fi
+],[
+	#
+	# Use Sniffer API if present, otherwise don't
+	#
+	want_snf=ifpresent
+])
+
+AC_ARG_WITH([snf-includes],
+AC_HELP_STRING([--with-snf-includes=DIR],[Myricom SNF include directory]),
+[
+	# User wants SNF with specific header directory
+	want_snf=yes
+	snf_include_dir=$withval
+],[])
+
+AC_ARG_WITH([snf-libraries],
+AC_HELP_STRING([--with-snf-libraries=DIR],[Myricom SNF library directory]),
+[
+	# User wants SNF with specific lib directory
+	want_snf=yes
+	snf_lib_dir=$withval
+],[])
+
+case "$V_PCAP" in
+bpf|linux|snf)
+	#
+	# We support the Sniffer API if we're on BSD, Linux, or if we're
+	# building a Sniffer-only libpcap.
+	#
+	;;
+*)
+	#
+	# If the user explicitly requested Sniffer, tell them it's not
+	# supported.
+	#
+	# If they expressed no preference, don't include it.
+	#
+	if test $want_snf = yes; then
+		AC_MSG_ERROR(Myricom SNF support only available with 'bpf' 'linux' and 'snf' packet capture types)
+	elif test $want_snf = yes; then
+		want_snf=no
+	fi
+	;;
+esac
+
+ac_cv_lbl_snf_api=no
+if test "$with_snf" != no; then
+
+	AC_MSG_CHECKING(whether we have Myricom Sniffer API)
+
+	if test -z "$snf_root"; then
+		snf_root=/opt/snf
+	fi
+
+	if test -z "$snf_include_dir"; then
+		snf_include_dir="$snf_root/include"
+	fi
+
+	if test -z "$snf_lib_dir"; then
+		snf_lib_dir="$snf_root/lib"
+	fi
+
+	if test -f "$snf_include_dir/snf.h"; then
+		ac_cv_lbl_snf_api=yes
+	fi
+	AC_MSG_RESULT([$ac_cv_lbl_snf_api ($snf_root)])
+
+	if test $ac_cv_lbl_snf_api = no; then
+		if test "$want_snf" = yes; then
+			AC_MSG_ERROR(SNF API headers not found under $snf_include_dir; use --without-snf)
+		fi
+	else
+		saved_ldflags=$LDFLAGS
+		LDFLAGS="$LDFLAGS -L$snf_lib_dir"
+		AC_CHECK_LIB([snf], [snf_init], [ac_cv_lbl_snf_api="yes"], [ac_cv_lbl_snf_api="no"])
+		LDFLAGS="$saved_ldflags"
+
+		if test $ac_cv_lbl_snf_api = no; then
+			if test "$want_snf" = yes; then
+				AC_MSG_ERROR(SNF API cannot correctly be linked check config.log; use --without-snf)
+			fi
+		else
+			V_INCLS="$V_INCLS -I$snf_include_dir"
+			LIBS="$LIBS -L$snf_lib_dir -lsnf"
+			AC_DEFINE(HAVE_SNF_API, 1, [define if you have Myricom SNF API])
+		fi
+	fi
+fi
+
+if test "$V_PCAP" = snf -a "$ac_cv_lbl_snf_api" = no; then
+	AC_MSG_ERROR(Specifying the capture type as 'snf' requires the Myricom Sniffer API to be present; use --with-snf=DIR)
+fi
 
 AC_LBL_LEX_AND_YACC(V_LEX, V_YACC, pcap_)
 if test "$V_LEX" = lex ; then
diff --git a/inet.c b/inet.c
index b21487b..e411cbe 100644
--- a/inet.c
+++ b/inet.c
@@ -671,6 +671,9 @@ pcap_lookupnet(device, netp, maskp, errbuf)
 #ifdef PCAP_SUPPORT_USB
 	    || strstr(device, "usbmon") != NULL
 #endif
+#ifdef HAVE_SNF_API
+	    || strstr(device, "snf") != NULL
+#endif
 	    ) {
 		*netp = *maskp = 0;
 		return 0;
diff --git a/pcap-bpf.c b/pcap-bpf.c
index 02aeec4..310256d 100644
--- a/pcap-bpf.c
+++ b/pcap-bpf.c
@@ -126,6 +126,10 @@ static int bpf_load(char *errbuf);
 #include "pcap-dag.h"
 #endif /* HAVE_DAG_API */
 
+#ifdef HAVE_SNF_API
+#include "pcap-snf.h"
+#endif /* HAVE_SNF_API */
+
 #ifdef HAVE_OS_PROTO_H
 #include "os-proto.h"
 #endif
@@ -417,6 +421,10 @@ pcap_create(const char *device, char *ebuf)
 	if (strstr(device, "dag"))
 		return (dag_create(device, ebuf));
 #endif /* HAVE_DAG_API */
+#ifdef HAVE_SNF_API
+	if (strstr(device, "snf"))
+		return (snf_create(device, ebuf));
+#endif /* HAVE_SNF_API */
 
 	p = pcap_create_common(device, ebuf);
 	if (p == NULL)
@@ -2170,6 +2178,10 @@ pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 	if (dag_platform_finddevs(alldevsp, errbuf) < 0)
 		return (-1);
 #endif /* HAVE_DAG_API */
+#ifdef HAVE_SNF_API
+	if (snf_platform_finddevs(alldevsp, errbuf) < 0)
+		return (-1);
+#endif /* HAVE_SNF_API */
 
 	return (0);
 }
diff --git a/pcap-int.h b/pcap-int.h
index 075e71a..c3afbad 100644
--- a/pcap-int.h
+++ b/pcap-int.h
@@ -56,6 +56,10 @@ extern CRITICAL_SECTION g_PcapCompileCriticalSection;
 #include <io.h>
 #endif
 
+#ifdef HAVE_SNF_API
+#include <snf.h>
+#endif
+
 #if (defined(_MSC_VER) && (_MSC_VER <= 1200)) /* we are compiling with Visual Studio 6, that doesn't support the LL suffix*/
 
 /*
@@ -162,6 +166,13 @@ struct pcap_md {
 				 * Same as in linux above, introduce
 				 * generally? */
 #endif /* HAVE_DAG_API */
+#ifdef HAVE_SNF_API
+	snf_handle_t snf_handle; /* opaque device handle */
+	snf_ring_t   snf_ring;   /* opaque device ring handle */
+        int          snf_timeout;
+        int          snf_boardnum;
+#endif /*HAVE_SNF_API*/
+
 #ifdef HAVE_ZEROCOPY_BPF
        /*
         * Zero-copy read buffer -- for zero-copy BPF.  'buffer' above will
diff --git a/pcap-linux.c b/pcap-linux.c
index 6df107d..af12543 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -170,6 +170,10 @@ static const char rcsid[] _U_ =
 #include "pcap-septel.h"
 #endif /* HAVE_SEPTEL_API */
 
+#ifdef HAVE_SNF_API
+#include "pcap-snf.h"
+#endif /* HAVE_SNF_API */
+
 #ifdef PCAP_SUPPORT_USB
 #include "pcap-usb-linux.h"
 #endif
@@ -376,6 +380,13 @@ pcap_create(const char *device, char *ebuf)
 	}
 #endif /* HAVE_SEPTEL_API */
 
+#ifdef HAVE_SNF_API
+        handle = snf_create(device, ebuf);
+        if (strstr(device, "snf") || handle != NULL)
+		return handle;
+
+#endif /* HAVE_SNF_API */
+
 #ifdef PCAP_SUPPORT_BT
 	if (strstr(device, "bluetooth")) {
 		return bt_create(device, ebuf);
@@ -2100,6 +2111,11 @@ pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf)
 		return (-1);
 #endif /* HAVE_SEPTEL_API */
 
+#ifdef HAVE_SNF_API
+	if (snf_platform_finddevs(alldevsp, errbuf) < 0)
+		return (-1);
+#endif /* HAVE_SNF_API */
+
 #ifdef PCAP_SUPPORT_BT
 	/*
 	 * Add Bluetooth devices.
diff --git a/pcap-snf.c b/pcap-snf.c
new file mode 100644
index 0000000..96781bd
--- /dev/null
+++ b/pcap-snf.c
@@ -0,0 +1,306 @@
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <sys/param.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+
+#include <ctype.h>
+#include <netinet/in.h>
+#include <sys/mman.h>
+#include <sys/socket.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "snf.h"
+#include "pcap-int.h"
+
+#ifdef SNF_ONLY
+#define snf_create pcap_create
+#define snf_platform_finddevs pcap_platform_finddevs
+#endif
+
+static int
+snf_set_datalink(pcap_t *p, int dlt)
+{
+	p->linktype = dlt;
+	return (0);
+}
+
+static int
+snf_pcap_stats(pcap_t *p, struct pcap_stat *ps)
+{
+	struct snf_ring_stats stats;
+	int rc;
+
+	if ((rc = snf_ring_getstats(p->md.snf_ring, &stats))) {
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snf_get_stats: %s",
+			 pcap_strerror(rc));
+		return -1;
+	}
+	ps->ps_recv = stats.ring_pkt_recv + stats.ring_pkt_overflow;
+	ps->ps_drop = stats.ring_pkt_overflow;
+	ps->ps_ifdrop = stats.nic_pkt_overflow + stats.nic_pkt_bad;
+	return 0;
+}
+
+static void
+snf_platform_cleanup(pcap_t *p)
+{
+	if (p == NULL)
+		return;
+
+	snf_ring_close(p->md.snf_ring);
+	snf_close(p->md.snf_handle);
+	pcap_cleanup_live_common(p);
+}
+
+static int
+snf_getnonblock(pcap_t *p, char *errbuf)
+{
+	return (p->md.snf_timeout == 0);
+}
+
+static int
+snf_setnonblock(pcap_t *p, int nonblock, char *errbuf)
+{
+	if (nonblock)
+		p->md.snf_timeout = 0;
+	else {
+		if (p->md.timeout <= 0)
+			p->md.snf_timeout = -1; /* forever */
+		else
+			p->md.snf_timeout = p->md.timeout;
+	}
+	return (0);
+}
+
+#define _NSEC_PER_SEC 1000000000
+
+static inline
+struct timeval
+snf_timestamp_to_timeval(const int64_t ts_nanosec)
+{
+	struct timeval tv;
+	int32_t rem;
+	if (ts_nanosec == 0)
+		return (struct timeval) { 0, 0 };
+	tv.tv_sec = ts_nanosec / _NSEC_PER_SEC;
+	tv.tv_usec = (ts_nanosec % _NSEC_PER_SEC) / 1000;
+	return tv;
+}
+
+static int
+snf_read(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
+{
+	struct pcap_pkthdr hdr;
+	int i, flags, err, caplen, n;
+	struct snf_recv_req req;
+
+	if (!p || cnt == 0)
+		return -1;
+
+	n = 0;
+	while (n < cnt || cnt < 0) {
+		/*
+		 * Has "pcap_breakloop()" been called?
+		 */
+		if (p->break_loop) {
+			if (n == 0) {
+				p->break_loop = 0;
+				return (-2);
+			} else {
+				return (n);
+			}
+		}
+
+		err = snf_ring_recv(p->md.snf_ring, p->md.snf_timeout, &req);
+
+		if (err) {
+			if (err == EBUSY || err == EAGAIN)
+				return (0);
+			if (err == EINTR)
+				continue;
+			if (err != 0) {
+				snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "snf_read: %s",
+				 	 pcap_strerror(err));
+				return -1;
+			}
+		}
+
+		caplen = req.length;
+		if (caplen > p->snapshot)
+			caplen = p->snapshot;
+
+		if ((p->fcode.bf_insns == NULL) ||
+		     bpf_filter(p->fcode.bf_insns, req.pkt_addr, req.length, caplen)) {
+			hdr.ts = snf_timestamp_to_timeval(req.timestamp);
+			hdr.caplen = caplen;
+			hdr.len = req.length;
+			callback(user, &hdr, req.pkt_addr);
+		}
+		n++;
+	}
+	return (n);
+}
+
+static int
+snf_setfilter(pcap_t *p, struct bpf_program *fp)
+{
+	if (!p)
+		return -1;
+	if (!fp) {
+		strncpy(p->errbuf, "setfilter: No filter specified",
+			sizeof(p->errbuf));
+		return -1;
+	}
+
+	/* Make our private copy of the filter */
+
+	if (install_bpf_program(p, fp) < 0)
+		return -1;
+
+	p->md.use_bpf = 0;
+
+	return (0);
+}
+
+static int
+snf_inject(pcap_t *p, const void *buf _U_, size_t size _U_)
+{
+	strlcpy(p->errbuf, "Sending packets isn't supported with snf",
+	    PCAP_ERRBUF_SIZE);
+	return (-1);
+}
+
+static int
+snf_activate(pcap_t* p)
+{
+	char *device = p->opt.source;
+	const char *nr = NULL;
+	int err;
+	int flags = 0;
+
+	if (device == NULL) {
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			 "device is NULL: %s", pcap_strerror(errno));
+		return -1;
+	}
+
+	/* In Libpcap, we set pshared by default if NUM_RINGS is set to > 1.
+	 * Since libpcap isn't thread-safe */
+	if ((nr = getenv("SNF_NUM_RINGS")) && *nr && atoi(nr) > 1)
+		flags |= SNF_F_PSHARED;
+	else
+		nr = NULL;
+
+	err = snf_open(p->md.snf_boardnum,
+			0, /* let SNF API parse SNF_NUM_RINGS, if set */
+			NULL, /* default RSS, or use SNF_RSS_FLAGS env */
+			0, /* default to SNF_DATARING_SIZE from env */
+			flags, /* may want pshared */
+			&p->md.snf_handle);
+	if (err != 0) {
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			 "snf_open failed: %s", pcap_strerror(err));
+		return -1;
+	}
+
+	err = snf_ring_open(p->md.snf_handle, &p->md.snf_ring);
+	if (err != 0) {
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			 "snf_ring_open failed: %s", pcap_strerror(err));
+		return -1;
+	}
+
+	if (p->md.timeout <= 0)
+		p->md.snf_timeout = -1;
+	else
+		p->md.snf_timeout = p->md.timeout;
+
+	err = snf_start(p->md.snf_handle);
+	if (err != 0) {
+		snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
+			 "snf_start failed: %s", pcap_strerror(err));
+		return -1;
+	}
+
+	/*
+	 * "select()" and "poll()" don't work on snf descriptors.
+	 */
+	p->selectable_fd = -1;
+	p->linktype = DLT_EN10MB;
+	p->read_op = snf_read;
+	p->inject_op = snf_inject;
+	p->setfilter_op = snf_setfilter;
+	p->setdirection_op = NULL; /* Not implemented.*/
+	p->set_datalink_op = snf_set_datalink;
+	p->getnonblock_op = snf_getnonblock;
+	p->setnonblock_op = snf_setnonblock;
+	p->stats_op = snf_pcap_stats;
+	p->cleanup_op = snf_platform_cleanup;
+	p->md.stat.ps_recv = 0;
+	p->md.stat.ps_drop = 0;
+	p->md.stat.ps_ifdrop = 0;
+	return 0;
+}
+
+int
+snf_platform_finddevs(pcap_if_t **devlistp, char *errbuf)
+{
+	/*
+	 * There are no platform-specific devices since each device
+	 * exists as a regular Ethernet device.
+	 */
+	return 0;
+}
+
+pcap_t *
+snf_create(const char *device, char *ebuf)
+{
+	pcap_t *p;
+	int boardnum = -1;
+	struct snf_ifaddrs *ifaddrs, *ifa;
+	size_t devlen;
+
+	if (snf_init(SNF_VERSION_API))
+		return NULL;
+
+	/*
+	 * Match a given interface name to our list of interface names, from
+	 * which we can obtain the intended board number
+	 */
+	if (snf_getifaddrs(&ifaddrs) || ifaddrs == NULL)
+		return NULL;
+	devlen = strlen(device) + 1;
+	ifa = ifaddrs;
+	while (ifa) {
+		if (!strncmp(device, ifa->snf_ifa_name, devlen)) {
+			boardnum = ifa->snf_ifa_boardnum;
+			break;
+		}
+		ifa = ifa->snf_ifa_next;
+	}
+	snf_freeifaddrs(ifaddrs);
+
+	if (ifa == NULL) {
+		/*
+		 * If we can't find the device by name, support the name "snfX"
+		 * and "snf10gX" where X is the board number.
+		 */
+		if (sscanf(device, "snf10g%d", &boardnum) != 1 &&
+		    sscanf(device, "snf%d", &boardnum) != 1)
+			return NULL;
+	}
+
+	p = pcap_create_common(device, ebuf);
+	if (p == NULL)
+		return NULL;
+
+	p->activate_op = snf_activate;
+	p->md.snf_boardnum = boardnum;
+	return p;
+}
diff --git a/pcap-snf.h b/pcap-snf.h
new file mode 100644
index 0000000..8c19755
--- /dev/null
+++ b/pcap-snf.h
@@ -0,0 +1,2 @@
+pcap_t *snf_create(const char *, char *);
+int snf_platform_finddevs(pcap_if_t **devlistp, char *errbuf);