Date: Thu, 23 May 2002 16:39:27 -0400 (EDT) From: Rob Manchester <rmanches@brown.edu> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/38473: src address in ipv4 hdr for multicast packets contain hosts group rather than hosts address Message-ID: <200205232039.g4NKdRLM005572@lester.manchero.org>
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>Number: 38473 >Category: kern >Synopsis: src address in ipv4 hdr for multicast packets contain hosts group rather than hosts address >Confidential: no >Severity: critical >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Thu May 23 16:50:01 PDT 2002 >Closed-Date: >Last-Modified: >Originator: Rob Manchester >Release: FreeBSD 4.6-RC i386 >Organization: >Environment: System: FreeBSD lester 4.6-RC FreeBSD 4.6-RC #21: Sat May 18 17:02:34 EDT 2002 rmanches@lester:/usr/obj/usr/src/sys/LESTER i386 >Description: according to section 6.2 of rfc1054, the source address in the ip header should contain the host's address rather than the host's group address. FreeBSD from at least 4.5->4.6rc sets the source address to the host group. I don't see a reason for doing this, and it causes incompatibility with other os's ipv4 mc implementaion, mainly linux. >How-To-Repeat: send out a mc packet using ipv4 and watch the outgoing packets using tcpdump. >Fix: if the src address is a multicast addres, set the address to that of the outgoing interface. Index: ip_output.c =================================================================== RCS file: /home/ncvs/src/sys/netinet/ip_output.c,v retrieving revision 1.157 diff -u -r1.157 ip_output.c --- ip_output.c 2002/05/21 18:52:24 1.157 +++ ip_output.c 2002/05/23 01:31:09 @@ -316,10 +316,11 @@ } } /* - * If source address not specified yet, use address - * of outgoing interface. + * If source address not specified yet, or it is a mc + * address, use the address of outgoing interface */ - if (ip->ip_src.s_addr == INADDR_ANY) { + if (ip->ip_src.s_addr == INADDR_ANY || + IN_MULTICAST(ntohl(ip->ip_src.s_addr))) { /* Interface may have no addresses. */ if (ia != NULL) ip->ip_src = IA_SIN(ia)->sin_addr; >Release-Note: >Audit-Trail: >Unformatted: To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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