feature: support packet dump to pcap

src/packet/packet_dump.cpp

@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <errno.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/time.h>
+
+#include "log.h"
+#include "packet_dump.h"
+
+#define PACKET_DUMP_LOG_ERROR(format, ...) LOG_ERROR("packet dump", format, ##__VA_ARGS__)
+
+struct pcap_pkt_hdr
+{
+    unsigned int tv_sec;  // time stamp
+    unsigned int tv_usec; // time stamp
+    unsigned int caplen;  // length of portion present
+    unsigned int len;     // length this packet (off wire)
+};
+
+struct pcap_file_hdr
+{
+    unsigned int magic;
+    unsigned short version_major;
+    unsigned short version_minor;
+    unsigned int thiszone; // gmt to local correction
+    unsigned int sigfigs;  // accuracy of timestamps
+    unsigned int snaplen;  // max length saved portion of each pkt
+    unsigned int linktype; // data link type (LINKTYPE_*)
+};
+
+// return  0: success
+// return -1: failed
+int packet_dump(const char *file, const char *data, uint16_t len)
+{
+    struct pcap_pkt_hdr pkt_hdr = {0};
+    struct pcap_file_hdr file_hdr = {
+        .magic = 0xA1B2C3D4,
+        .version_major = 0x0002,
+        .version_minor = 0x0004,
+        .thiszone = 0,
+        .sigfigs = 0,
+        .snaplen = 0xFFFF,
+        .linktype = 1};
+
+    if (file == NULL || data == NULL || len == 0)
+    {
+        PACKET_DUMP_LOG_ERROR("invalid parameter, file: %p, data: %p, len: %d", file, data, len);
+        return -1;
+    }
+
+    FILE *fp = fopen(file, "w+");
+    if (fp == NULL)
+    {
+        PACKET_DUMP_LOG_ERROR("fopen %s failed, %s", file, strerror(errno));
+        return -1;
+    }
+
+    struct timeval ts = {0};
+    gettimeofday(&ts, NULL);
+
+    pkt_hdr.tv_sec = ts.tv_sec;
+    pkt_hdr.tv_usec = ts.tv_usec;
+    pkt_hdr.caplen = len;
+    pkt_hdr.len = len;
+
+    fwrite(&file_hdr, sizeof(struct pcap_file_hdr), 1, fp);
+    fwrite(&pkt_hdr, sizeof(struct pcap_pkt_hdr), 1, fp);
+    fwrite(data, 1, len, fp);
+    fflush(fp);
+    fclose(fp);
+
+    return 0;
+}