Date: Wed, 24 Jul 1996 09:12:06 +0900 From: Toshihiro Kanda <candy@fct.kgc.co.jp> To: "K.V.S. Sankaram" <kasturi@teil.soft.net> Cc: hackers@FreeBSD.org Subject: Re: How to use BPF ? Message-ID: <199607240012.JAA00403@xxx.fct.kgc.co.jp> In-Reply-To: "K.V.S. Sankaram"'s message of 23 Jul 1996 19:29:01 %2B0900 References: <Pine.SGI.3.93.960723142034.11451D-100000@teil.soft.net>
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> I am facing problems in sending packets through BPF. Can anybody give me
>
> some idea (or steps) as to how to configure BPF and send packets through it ?
static struct bpf_program prog;
First, initialize prog. Then,
char *name = "ed0";
fd = open("/dev/bpf0", O_RDWR);
if (fd >= 0) {
struct bpf_version ver;
if (ioctl(fd, BIOCVERSION, &ver) == 0) {
if (BPF_MAJOR_VERSION == ver.bv_major && BPF_MINOR_VERSION <= ver.bv_minor) {
unsigned int blen = BPF_BUFFER_SIZE;
if (ioctl(fd, BIOCSBLEN, &blen) == 0) {
struct ifreq ifr;
strncpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
if (ioctl(fd, BIOCSETIF, &ifr) == 0) {
unsigned int im = 1;
if (ioctl(fd, BIOCIMMEDIATE, &im) == 0) {
if (ioctl(fd, BIOCSETF, prog) == 0) {
err = fd;
}
}
}
}
}
}
if (err < 0)
close(fd);
}
: : :
write(fd, data, length);
Note: data[12] and data[13] (ether type) must be host byte order (NOT
network byte order). I believe this is a bug, though FreeBSD core
team don't think so.
candy@fct.kgc.co.jp (Toshihiro Kanda)
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