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authorDavid Gibson <david@gibson.dropbear.id.au>2023-01-06 11:43:05 +1100
committerStefano Brivio <sbrivio@redhat.com>2023-01-23 18:48:51 +0100
commitcb3c1ce30760aff10a4952a1c3b85f61a6eeacfd (patch)
treeb850d0195f3c653bc9969733c628959c90fa6262
parentb93d025d50dcc2c058b9eb3b67b76da56d27fcba (diff)
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pcap: Introduce pcap_frame() helper
pcap(), pcapm() and pcapmm() duplicate some code, for the actual writing to the capture file. The purpose of pcapm() and pcapmm() not calling pcap() seems to be to avoid repeatedly calling gettimeofday() and to avoid printing errors for every packet in a batch if there's a problem. We can accomplish that while still sharing code by adding a new helper which takes the packet timestamp as a parameter. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
-rw-r--r--pcap.c76
1 files changed, 38 insertions, 38 deletions
diff --git a/pcap.c b/pcap.c
index 836688d..0c6dc89 100644
--- a/pcap.c
+++ b/pcap.c
@@ -66,24 +66,41 @@ struct pcap_pkthdr {
};
/**
+ * pcap_frame() - Capture a single frame to pcap file with given timestamp
+ * @pkt: Pointer to data buffer, including L2 headers
+ * @len: L2 packet length
+ * @tv: Timestamp
+ *
+ * Returns: 0 on success, -errno on error writing to the file
+ */
+static int pcap_frame(const char *pkt, size_t len, const struct timeval *tv)
+{
+ struct pcap_pkthdr h;
+
+ h.tv_sec = tv->tv_sec;
+ h.tv_usec = tv->tv_usec;
+ h.caplen = h.len = len;
+
+ if (write(pcap_fd, &h, sizeof(h)) < 0 || write(pcap_fd, pkt, len) < 0)
+ return -errno;
+
+ return 0;
+}
+
+/**
* pcap() - Capture a single frame to pcap file
* @pkt: Pointer to data buffer, including L2 headers
* @len: L2 packet length
*/
void pcap(const char *pkt, size_t len)
{
- struct pcap_pkthdr h;
struct timeval tv;
if (pcap_fd == -1)
return;
gettimeofday(&tv, NULL);
- h.tv_sec = tv.tv_sec;
- h.tv_usec = tv.tv_usec;
- h.caplen = h.len = len;
-
- if (write(pcap_fd, &h, sizeof(h)) < 0 || write(pcap_fd, pkt, len) < 0)
+ if (pcap_frame(pkt, len, &tv) != 0)
debug("Cannot log packet, length %lu", len);
}
@@ -93,8 +110,6 @@ void pcap(const char *pkt, size_t len)
*/
void pcapm(const struct msghdr *mh)
{
- struct pcap_pkthdr h;
- struct iovec *iov;
struct timeval tv;
unsigned int i;
@@ -102,24 +117,17 @@ void pcapm(const struct msghdr *mh)
return;
gettimeofday(&tv, NULL);
- h.tv_sec = tv.tv_sec;
- h.tv_usec = tv.tv_usec;
for (i = 0; i < mh->msg_iovlen; i++) {
- iov = &mh->msg_iov[i];
+ const struct iovec *iov = &mh->msg_iov[i];
- h.caplen = h.len = iov->iov_len - 4;
-
- if (write(pcap_fd, &h, sizeof(h)) < 0)
- goto fail;
- if (write(pcap_fd, (char *)iov->iov_base + 4,
- iov->iov_len - 4) < 0)
- goto fail;
+ if (pcap_frame((char *)iov->iov_base + 4,
+ iov->iov_len - 4, &tv) != 0) {
+ debug("Cannot log packet, length %lu",
+ iov->iov_len - 4);
+ return;
+ }
}
-
- return;
-fail:
- debug("Cannot log packet, length %lu", iov->iov_len - 4);
}
/**
@@ -128,8 +136,6 @@ fail:
*/
void pcapmm(const struct mmsghdr *mmh, unsigned int vlen)
{
- struct pcap_pkthdr h;
- struct iovec *iov;
struct timeval tv;
unsigned int i, j;
@@ -137,27 +143,21 @@ void pcapmm(const struct mmsghdr *mmh, unsigned int vlen)
return;
gettimeofday(&tv, NULL);
- h.tv_sec = tv.tv_sec;
- h.tv_usec = tv.tv_usec;
for (i = 0; i < vlen; i++) {
const struct msghdr *mh = &mmh[i].msg_hdr;
for (j = 0; j < mh->msg_iovlen; j++) {
- iov = &mh->msg_iov[j];
-
- h.caplen = h.len = iov->iov_len - 4;
-
- if (write(pcap_fd, &h, sizeof(h)) < 0)
- goto fail;
- if (write(pcap_fd, (char *)iov->iov_base + 4,
- iov->iov_len - 4) < 0)
- goto fail;
+ const struct iovec *iov = &mh->msg_iov[j];
+
+ if (pcap_frame((char *)iov->iov_base + 4,
+ iov->iov_len - 4, &tv) != 0) {
+ debug("Cannot log packet, length %lu",
+ iov->iov_len - 4);
+ return;
+ }
}
}
- return;
-fail:
- debug("Cannot log packet, length %lu", iov->iov_len - 4);
}
/**