1 files changed, 49 insertions, 37 deletions

diff --git a/pcap.c b/pcap.c
index 3d623cf..e4b47ce 100644
--- a/pcap.c
+++ b/pcap.c
@@ -33,32 +33,12 @@
 #include "log.h"
 #include "pcap.h"
 #include "iov.h"
+#include "tap.h"
+#include "serialise.h"
 
 #define PCAP_VERSION_MINOR 4
 
-static int pcap_fd = -1;
-
-/* See pcap.h from libpcap, or pcap-savefile(5) */
-static const struct {
-	uint32_t magic;
-#define PCAP_MAGIC		0xa1b2c3d4
-
-	uint16_t major;
-#define PCAP_VERSION_MAJOR	2
-
-	uint16_t minor;
-#define PCAP_VERSION_MINOR	4
-
-	int32_t thiszone;
-	uint32_t sigfigs;
-	uint32_t snaplen;
-
-	uint32_t linktype;
-#define PCAP_LINKTYPE_ETHERNET	1
-} pcap_hdr = {
-	PCAP_MAGIC, PCAP_VERSION_MAJOR, PCAP_VERSION_MINOR, 0, 0, ETH_MAX_MTU,
-	PCAP_LINKTYPE_ETHERNET
-};
+int pcap_fd = -1;
 
 struct pcap_pkthdr {
 	uint32_t tv_sec;
@@ -72,14 +52,12 @@ struct pcap_pkthdr {
  * @iov:	IO vector containing frame (with L2 headers and tap headers)
  * @iovcnt:	Number of buffers (@iov entries) in frame
  * @offset:	Byte offset of the L2 headers within @iov
+ * @l2len:	Length of L2 frame data to capture
  * @now:	Timestamp
- *
- * Returns: 0 on success, -errno on error writing to the file
  */
 static void pcap_frame(const struct iovec *iov, size_t iovcnt,
-		       size_t offset, const struct timespec *now)
+		       size_t offset, size_t l2len, const struct timespec *now)
 {
-	size_t l2len = iov_size(iov, iovcnt) - offset;
 	struct pcap_pkthdr h = {
 		.tv_sec = now->tv_sec,
 		.tv_usec = DIV_ROUND_CLOSEST(now->tv_nsec, 1000),
@@ -87,9 +65,15 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt,
 		.len = l2len
 	};
 
-	if (write_all_buf(pcap_fd, &h, sizeof(h)) < 0 ||
-	    write_remainder(pcap_fd, iov, iovcnt, offset) < 0)
+	if (write_all_buf(pcap_fd, &h, sizeof(h)) < 0) {
+		debug_perror("Cannot log packet, packet header error");
+		return;
+	}
+
+	if (write_remainder(pcap_fd, iov, iovcnt, offset, l2len) < 0) {
 		debug_perror("Cannot log packet, length %zu", l2len);
+		return;
+	}
 }
 
 /**
@@ -97,6 +81,7 @@ static void pcap_frame(const struct iovec *iov, size_t iovcnt,
  * @pkt:	Pointer to data buffer, including L2 headers
  * @l2len:	L2 frame length
  */
+/* cppcheck-suppress unusedFunction */
 void pcap(const char *pkt, size_t l2len)
 {
 	struct iovec iov = { (char *)pkt, l2len };
@@ -108,7 +93,7 @@ void pcap(const char *pkt, size_t l2len)
 	if (clock_gettime(CLOCK_REALTIME, &now))
 		err_perror("Failed to get CLOCK_REALTIME time");
 
-	pcap_frame(&iov, 1, 0, &now);
+	pcap_frame(&iov, 1, 0, l2len, &now);
 }
 
 /**
@@ -130,20 +115,24 @@ void pcap_multiple(const struct iovec *iov, size_t frame_parts, unsigned int n,
 	if (clock_gettime(CLOCK_REALTIME, &now))
 		err_perror("Failed to get CLOCK_REALTIME time");
 
-	for (i = 0; i < n; i++)
-		pcap_frame(iov + i * frame_parts, frame_parts, offset, &now);
+	for (i = 0; i < n; i++) {
+		pcap_frame(iov + i * frame_parts, frame_parts, offset,
+			   iov_size(iov + i * frame_parts, frame_parts) - offset,
+			   &now);
+	}
 }
 
-/*
- * pcap_iov - Write packet data described by an I/O vector
+/**
+ * pcap_iov() - Write packet data described by an I/O vector
  *		to a pcap file descriptor.
- *
  * @iov:	Pointer to the array of struct iovec describing the I/O vector
  *		containing packet data to write, including L2 header
  * @iovcnt:	Number of buffers (@iov entries)
  * @offset:	Offset of the L2 frame within the full data length
+ * @l2len:	Length of L2 frame data to capture
  */
-void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
+void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset,
+	      size_t l2len)
 {
 	struct timespec now = { 0 };
 
@@ -153,7 +142,7 @@ void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
 	if (clock_gettime(CLOCK_REALTIME, &now))
 		err_perror("Failed to get CLOCK_REALTIME time");
 
-	pcap_frame(iov, iovcnt, offset, &now);
+	pcap_frame(iov, iovcnt, offset, l2len, &now);
 }
 
 /**
@@ -162,6 +151,29 @@ void pcap_iov(const struct iovec *iov, size_t iovcnt, size_t offset)
  */
 void pcap_init(struct ctx *c)
 {
+	/* See pcap.h from libpcap, or pcap-savefile(5) */
+#define PCAP_MAGIC		0xa1b2c3d4
+#define PCAP_VERSION_MAJOR	2
+#define PCAP_VERSION_MINOR	4
+#define PCAP_LINKTYPE_ETHERNET	1
+	const struct {
+		uint32_t magic;
+		uint16_t major;
+		uint16_t minor;
+
+		int32_t thiszone;
+		uint32_t sigfigs;
+		uint32_t snaplen;
+
+		uint32_t linktype;
+	} pcap_hdr = {
+		.magic = PCAP_MAGIC,
+		.major = PCAP_VERSION_MAJOR,
+		.minor = PCAP_VERSION_MINOR,
+		.snaplen = tap_l2_max_len(c),
+		.linktype = PCAP_LINKTYPE_ETHERNET
+	};
+
 	if (pcap_fd != -1)
 		return;