Mercurial > hg > dhcpcd
changeset 4454:1037d1e35cd8 draft
BPF: Set flag indicate whether the packet was broadcast or not
| author | Roy Marples <roy@marples.name> |
|---|---|
| date | Thu, 18 Apr 2019 16:56:34 +0100 |
| parents | 00fb50fd1a45 |
| children | 767d7b8a78cb |
| files | src/bpf.c src/bpf.h |
| diffstat | 2 files changed, 25 insertions(+), 3 deletions(-) [+] |
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--- a/src/bpf.c Thu Apr 18 14:54:47 2019 +0100 +++ b/src/bpf.c Thu Apr 18 16:56:34 2019 +0100 @@ -84,7 +84,7 @@ bpf_frame_header_len(const struct interface *ifp) { - switch(ifp->family) { + switch (ifp->family) { case ARPHRD_ETHER: return sizeof(struct ether_header); default: @@ -92,6 +92,23 @@ } } +static const uint8_t etherbroadcastaddr[] = + { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff }; + +static int +bpf_frame_bcast(const struct interface *ifp, const char *frame) +{ + + switch (ifp->family) { + case ARPHRD_ETHER: + return memcmp(frame + + offsetof(struct ether_header, ether_dhost), + etherbroadcastaddr, sizeof(etherbroadcastaddr)); + default: + return -1; + } +} + #ifndef __linux__ /* Linux is a special snowflake for opening, attaching and reading BPF. * See if-linux.c for the Linux specific BPF functions. */ @@ -227,8 +244,12 @@ if (state->buffer_pos + packet.bh_caplen + packet.bh_hdrlen > state->buffer_len) goto next; /* Packet beyond buffer, drop. */ - payload = state->buffer + state->buffer_pos + - packet.bh_hdrlen + fl; + payload = state->buffer + state->buffer_pos + packet.bh_hdrlen; + if (bpf_frame_bcast(ifp, payload) == 0) + *flags |= BPF_BCAST; + else + *flags &= ~BPF_BCAST; + payload += fl; bytes = (ssize_t)packet.bh_caplen - fl; if ((size_t)bytes > len) bytes = (ssize_t)len;