57 lines
1.4 KiB
C
57 lines
1.4 KiB
C
#include <stdio.h>
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#include <stdint.h>
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#include <sys/time.h>
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typedef struct pcap_hdr_s {
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uint32_t magic_number; /* magic number */
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uint16_t version_major; /* major version number */
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uint16_t version_minor; /* minor version number */
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int32_t thiszone; /* GMT to local correction */
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uint32_t sigfigs; /* accuracy of timestamps */
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uint32_t snaplen; /* max length of captured packets, in octets */
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uint32_t network; /* data link type */
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} __attribute__((packed)) pcap_hdr_t;
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typedef struct pcaprec_hdr_s {
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uint32_t ts_sec; /* timestamp seconds */
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uint32_t ts_usec; /* timestamp microseconds */
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uint32_t incl_len; /* number of octets of packet saved in file */
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uint32_t orig_len; /* actual length of packet */
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} __attribute__((packed)) pcaprec_hdr_t;
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static FILE *f=NULL;
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void sniff_open(char *name) {
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f=fopen(name, "wb");
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if (f==NULL) {
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perror(name);
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exit(1);
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}
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pcap_hdr_t hdr={
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.magic_number=0xa1b2c3d4,
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.version_major=2,
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.version_minor=4,
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.thiszone=0,
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.sigfigs=0,
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.snaplen=65535,
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.network=1
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};
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fwrite(&hdr, sizeof(hdr), 1, f);
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}
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void sniff_write(uint8_t *buff, int len) {
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struct timeval tv;
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gettimeofday(&tv, NULL);
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pcaprec_hdr_t hdr={
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.ts_sec=tv.tv_sec,
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.ts_usec=tv.tv_usec,
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.incl_len=len,
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.orig_len=len,
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};
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fwrite(&hdr, sizeof(hdr), 1, f);
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fwrite(buff, len, 1, f);
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fflush(f);
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}
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