monitor: Handle timestamp and real packet length information

monitor/main.c

@@ -139,13 +139,20 @@ static struct l_netlink *genl_lookup(const char *ifname)
 	return genl;
 }
 
+#define MAX_SNAPLEN (1024 * 16)
+
 static int process_pcap(struct pcap *pcap)
 {
 	struct nlmon *nlmon = NULL;
+	struct timeval tv;
 	uint8_t *buf;
-	uint32_t len;
+	uint32_t snaplen, len, real_len;
 
-	buf = malloc(1024 * 16);
+	snaplen = pcap_get_snaplen(pcap);
+	if (snaplen > MAX_SNAPLEN)
+		snaplen = MAX_SNAPLEN;
+
+	buf = malloc(snaplen);
 	if (!buf) {
 		fprintf(stderr, "Failed to allocate packet buffer\n");
 		return EXIT_FAILURE;
@@ -153,7 +160,7 @@ static int process_pcap(struct pcap *pcap)
 
 	nlmon = nlmon_create();
 
-	while (pcap_read(pcap, NULL, buf, 1024 * 16, &len)) {
+	while (pcap_read(pcap, &tv, buf, snaplen, &len, &real_len)) {
 		uint16_t arphrd_type;
 		uint16_t proto_type;
 
@@ -162,6 +169,9 @@ static int process_pcap(struct pcap *pcap)
 			continue;
 		}
 
+		if (len < real_len)
+			printf("Packet truncated from %u\n", real_len);
+
 		arphrd_type = L_GET_UNALIGNED((const uint16_t *) (buf + 2));
 
 		if (L_BE16_TO_CPU(arphrd_type) != ARPHRD_NETLINK) {
@@ -174,10 +184,10 @@ static int process_pcap(struct pcap *pcap)
 
 		switch (L_BE16_TO_CPU(proto_type)) {
 		case NETLINK_ROUTE:
-			nlmon_print_rtnl(nlmon, buf, len);
+			nlmon_print_rtnl(nlmon, &tv, buf, len);
 			break;
 		case NETLINK_GENERIC:
-			nlmon_print_genl(nlmon, buf + 16, len - 16);
+			nlmon_print_genl(nlmon, &tv, buf + 16, len - 16);
 			break;
 		}
 	}

monitor/nlmon.c

@@ -1429,16 +1429,18 @@ static void genl_ctrl(struct nlmon *nlmon, const void *data, uint32_t len)
 		nlmon->id = id;
 }
 
-void nlmon_print_rtnl(struct nlmon *nlmon, const void *data, uint32_t size)
+void nlmon_print_rtnl(struct nlmon *nlmon, const struct timeval *tv,
+					const void *data, uint32_t size)
 {
 	char str[16];
 
 	sprintf(str, "len %u", size);
 
-	print_packet(NULL, '*', COLOR_WHITE, "Route Netlink", str, "");
+	print_packet(tv, '*', COLOR_WHITE, "Route Netlink", str, "");
 }
 
-void nlmon_print_genl(struct nlmon *nlmon, const void *data, uint32_t size)
+void nlmon_print_genl(struct nlmon *nlmon, const struct timeval *tv,
+					const void *data, uint32_t size)
 {
 	const struct nlmsghdr *nlmsg;
 
@@ -1448,7 +1450,7 @@ void nlmon_print_genl(struct nlmon *nlmon, const void *data, uint32_t size)
 			genl_ctrl(nlmon, NLMSG_DATA(nlmsg),
 						NLMSG_PAYLOAD(nlmsg, 0));
 		else
-			nlmon_message(nlmon, NULL, NULL, nlmsg);
+			nlmon_message(nlmon, tv, NULL, nlmsg);
 	}
 }
 

monitor/nlmon.h

@@ -21,6 +21,7 @@
  */
 
 #include <stdint.h>
+#include <sys/time.h>
 
 struct nlmon;
 
@@ -29,5 +30,7 @@ void nlmon_close(struct nlmon *nlmon);
 
 struct nlmon *nlmon_create(void);
 void nlmon_destroy(struct nlmon *nlmon);
-void nlmon_print_rtnl(struct nlmon *nlmon, const void *data, uint32_t size);
-void nlmon_print_genl(struct nlmon *nlmon, const void *data, uint32_t size);
+void nlmon_print_rtnl(struct nlmon *nlmon, const struct timeval *tv,
+					const void *data, uint32_t size);
+void nlmon_print_genl(struct nlmon *nlmon, const struct timeval *tv,
+					const void *data, uint32_t size);

monitor/pcap.c

@@ -133,7 +133,7 @@ uint32_t pcap_get_snaplen(struct pcap *pcap)
 }
 
 bool pcap_read(struct pcap *pcap, struct timeval *tv,
-				void *data, uint32_t size, uint32_t *len)
+		void *data, uint32_t size, uint32_t *len, uint32_t *real_len)
 {
 	struct pcap_pkt pkt;
 	uint32_t toread;
@@ -166,5 +166,8 @@ bool pcap_read(struct pcap *pcap, struct timeval *tv,
 	if (len)
 		*len = toread;
 
+	if (real_len)
+		*real_len = pkt.incl_len;
+
 	return true;
 }

monitor/pcap.h

@@ -37,4 +37,4 @@ uint32_t pcap_get_type(struct pcap *pcap);
 uint32_t pcap_get_snaplen(struct pcap *pcap);
 
 bool pcap_read(struct pcap *pcap, struct timeval *tv,
-				void *data, uint32_t size, uint32_t *len);
+		void *data, uint32_t size, uint32_t *len, uint32_t *real_len);