Hi, I'd like to get rid of this mbuf field "m->m_pkthdr.header". Here are my reasons:
- It's broken. Consider this code: copy = m_copypacket(m); m_freem(m); Typically m->m_pkthdr.header points into the data area of 'm'. So now copy->m_pkthdr.header points at the same data, which has already been freed and possibly reused. - It is an obscure thing most people don't know about and is ripe for causing hard to find bugs. - It's only used in two places, (a) for secret communication between the oltr driver and if_ether.c, and (b) as a temporary variable in ip_input.c: $ find . -type f -print | xargs grep -w m_pkthdr.header ./contrib/dev/oltr/if_oltr.c: m0->m_pkthdr.header = (void *)th; ./netinet/if_ether.c: th = (struct iso88025_header *)m->m_pkthdr.header; ./netinet/ip_input.c: m->m_pkthdr.header = ip; ./netinet/ip_input.c:#define GETIP(m) ((struct ip*)((m)->m_pkthdr.header)) My proposal: - Replace the obfuscating GETIP() macro in ip_input.c with a variable. - Rejigger the oltr driver to pass its "secret" information using an auxillary mbuf instead of m->m_pkthdr.header. Any comments/objections? Thanks, -Archie __________________________________________________________________________ Archie Cobbs * Packet Design * http://www.packetdesign.com To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-net" in the body of the message