From owner-freebsd-questions  Thu Sep  3 01:36:06 1998
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Date: Thu, 3 Sep 1998 16:07:57 +0800 (HKT)
From: "Canicula. Roel M." <09533893@mail4.dlsu.edu.ph>
To: questions@FreeBSD.ORG
Subject: BPF
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Greetings!
I'm Roel Canicula from De La Salle University in Manila, Philippines.
I've been trying to port my linux packet capture routines to work under
FreeBSD. I have read the bpf manual page and came up with the following
code:

void main() {
  int fd;
  struct ifreq ifr;
  char buf[500];

/* Open /dev/bpf0 */
  if ((fd=open("/dev/bpf0", O_RDONLY))==-1) {
    perror("open");
    exit(1);
  }

/* Bind file descriptor to network interface (eb0) */
  strcpy(ifr.ifr_name, "eb0");
  if (ioctl(fd, BIOCSETIF, &ifr)==-1) {
    perror("BIOCSETIF");
    exit(1);
  }

/* Listen for packets */
  if (read(fd, buf, 500)==-1) {
    perror("read");
    exit(1);
  }

  ...
}

The read() function returns an error and sets errno to EINVAL. I can't
figure out what's wrong with the code. I'd really appreciate it if you
could tell me how to make it work.  Thank you very much.

						Roel Canicula


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