mctp-demux-daemon: Add packet capture option
Optionally enable libpcap support in mctp-demux-daemon to capture
packets both from the Unix domain socket and binding interfaces.
Providing the two capture points allows for tracking down issues with
packets being dropped during binding initialisation.
As there's no formal linktype defined for MCTP or higher-level DMTF
protocols command-line switches provide the ability to specify one of
the private linktype values in the range 147-162.
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Change-Id: I593d9e4be80c0198e643758f216e774169668a8c
diff --git a/utils/mctp-capture.c b/utils/mctp-capture.c
new file mode 100644
index 0000000..e1c270e
--- /dev/null
+++ b/utils/mctp-capture.c
@@ -0,0 +1,78 @@
+#include "utils/mctp-capture.h"
+
+#include <stdio.h>
+#include <sys/time.h>
+
+int capture_init(void)
+{
+ char errbuf[PCAP_ERRBUF_SIZE];
+ int rc;
+
+ if ((rc = pcap_init(PCAP_CHAR_ENC_UTF_8, errbuf)) == -1) {
+ fprintf(stderr, "pcap_init: %s\n", errbuf);
+ return -1;
+ }
+
+ return 0;
+}
+
+int capture_prepare(struct capture *cap)
+{
+ int rc;
+
+ if (cap->linktype < CAPTURE_LINKTYPE_FIRST ||
+ cap->linktype > CAPTURE_LINKTYPE_LAST) {
+ fprintf(stderr,
+ "Invalid private linktype value %d: see https://www.tcpdump.org/linktypes.html\n",
+ cap->linktype);
+ return -1;
+ }
+
+ if (!(cap->pcap = pcap_open_dead(cap->linktype, UINT16_MAX))) {
+ fprintf(stderr, "pcap_open_dead: failed\n");
+ return -1;
+ }
+
+ if (!(cap->dumper = pcap_dump_open(cap->pcap, cap->path))) {
+ fprintf(stderr, "pcap_dump_open: failed\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+void capture_close(struct capture *cap)
+{
+ pcap_dump_close(cap->dumper);
+
+ pcap_close(cap->pcap);
+}
+
+void capture_binding(struct mctp_pktbuf *pkt, void *user)
+{
+ pcap_dumper_t *dumper = user;
+ struct pcap_pkthdr hdr;
+ int rc;
+
+ if ((rc = gettimeofday(&hdr.ts, NULL)) == -1)
+ return;
+
+ hdr.caplen = mctp_pktbuf_size(pkt);
+ hdr.len = mctp_pktbuf_size(pkt);
+
+ pcap_dump((u_char *)dumper, &hdr, (const u_char *)mctp_pktbuf_hdr(pkt));
+}
+
+void capture_socket(pcap_dumper_t *dumper, const void *buf, size_t len)
+{
+ struct pcap_pkthdr hdr;
+ int rc;
+
+ if ((rc = gettimeofday(&hdr.ts, NULL)) == -1)
+ return;
+
+ hdr.caplen = len;
+ hdr.len = len;
+
+ pcap_dump((u_char *)dumper, &hdr, buf);
+}