From: Jakub Zawadzki <darkjames@darkjames.pl>
Date: Wed, 1 May 2013 17:10:17 +0000 (+0200)
Subject: [Linux] add new function linux_check_direction()
X-Git-Tag: libpcap-1.5.0~56^2~21
X-Git-Url: https://git.tcpdump.org/libpcap/commitdiff_plain/43a4a4d17dab8168a08f30cbbbfed87e9e274d1f

[Linux] add new function linux_check_direction()

We're right now have the same code in two places, split it into new inline
function: linux_check_direction()

Merged-with-my-pcap_t-changes-by: Guy Harris <guy@alum.mit.edu>
---

diff --git a/pcap-linux.c b/pcap-linux.c
index e49af804..9fe97f30 100644
--- a/pcap-linux.c
+++ b/pcap-linux.c
@@ -1377,6 +1377,42 @@ pcap_set_datalink_linux(pcap_t *handle, int dlt)
 	return 0;
 }
 
+/*
+ * linux_check_direction()
+ *
+ * Do checks based on packet direction.
+ */
+static inline int
+linux_check_direction(const pcap_t *handle, const struct sockaddr_ll *sll)
+{
+	struct pcap_linux	*handlep = handle->private;
+
+	if (sll->sll_pkttype == PACKET_OUTGOING) {
+		/*
+		 * Outgoing packet.
+		 * If this is from the loopback device, reject it;
+		 * we'll see the packet as an incoming packet as well,
+		 * and we don't want to see it twice.
+		 */
+		if (sll->sll_ifindex == handlep->lo_ifindex)
+			return 0;
+
+		/*
+		 * If the user only wants incoming packets, reject it.
+		 */
+		if (handle->direction == PCAP_D_IN)
+			return 0;
+	} else {
+		/*
+		 * Incoming packet.
+		 * If the user only wants outgoing packets, reject it.
+		 */
+		if (handle->direction == PCAP_D_OUT)
+			return 0;
+	}
+	return 1;
+}
+
 /*
  *  Read a packet from the socket calling the handler provided by
  *  the user. Returns the number of packets received or -1 if an
@@ -1531,29 +1567,8 @@ pcap_read_packet(pcap_t *handle, pcap_handler callback, u_char *userdata)
 		 * address returned for SOCK_PACKET is a "sockaddr_pkt"
 		 * which lacks the relevant packet type information.
 		 */
-		if (from.sll_pkttype == PACKET_OUTGOING) {
-			/*
-			 * Outgoing packet.
-			 * If this is from the loopback device, reject it;
-			 * we'll see the packet as an incoming packet as well,
-			 * and we don't want to see it twice.
-			 */
-			if (from.sll_ifindex == handlep->lo_ifindex)
-				return 0;
-
-			/*
-			 * If the user only wants incoming packets, reject it.
-			 */
-			if (handle->direction == PCAP_D_IN)
-				return 0;
-		} else {
-			/*
-			 * Incoming packet.
-			 * If the user only wants outgoing packets, reject it.
-			 */
-			if (handle->direction == PCAP_D_OUT)
-				return 0;
-		}
+		if (!linux_check_direction(handle, &from))
+			return 0;
 	}
 #endif
 
@@ -4000,33 +4015,9 @@ pcap_read_linux_mmap(pcap_t *handle, int max_packets, pcap_handler callback,
 					tp_len, tp_snaplen) == 0))
 			goto skip;
 
-		/*
-		 * Do checks based on packet direction.
-		 */
 		sll = (void *)h.raw + TPACKET_ALIGN(handlep->tp_hdrlen);
-		if (sll->sll_pkttype == PACKET_OUTGOING) {
-			/*
-			 * Outgoing packet.
-			 * If this is from the loopback device, reject it;
-			 * we'll see the packet as an incoming packet as well,
-			 * and we don't want to see it twice.
-			 */
-			if (sll->sll_ifindex == handlep->lo_ifindex)
-				goto skip;
-
-			/*
-			 * If the user only wants incoming packets, reject it.
-			 */
-			if (handle->direction == PCAP_D_IN)
-				goto skip;
-		} else {
-			/*
-			 * Incoming packet.
-			 * If the user only wants outgoing packets, reject it.
-			 */
-			if (handle->direction == PCAP_D_OUT)
-				goto skip;
-		}
+		if (!linux_check_direction(handle, sll))
+			goto skip;
 
 		/* get required packet info from ring header */
 		pcaphdr.ts.tv_sec = tp_sec;