Date: Fri, 7 May 2004 17:30:34 -0700 From: Luigi Rizzo <rizzo@icir.org> To: Andre Oppermann <andre@freebsd.org> Cc: Mike Tancsa <mike@sentex.net> Subject: Re: routing bug? Message-ID: <20040507173034.A17825@xorpc.icir.org> In-Reply-To: <409BFBD5.5050101@freebsd.org>; from andre@freebsd.org on Fri, May 07, 2004 at 11:12:53PM %2B0200 References: <6.0.3.0.0.20040507151017.08816e60@64.7.153.2> <409BFBD5.5050101@freebsd.org>
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On Fri, May 07, 2004 at 11:12:53PM +0200, Andre Oppermann wrote:
> Mike Tancsa wrote:
...
> I hope this explains the effect you are seeing. A backport or MFC of
> the protocol cloning removal is not possible and is a rather extensive
> change to the network stack which is outside of the RELENG_4 scope.
actually my student Alessandro Cerri did just that, though I am
not sure if there is interest in committing it...
It all depends on what's the expected lifetime of 4.x
and whether 5.x gets "up to speed" reasonably...
cheers
luigi
> There is one easy hack you can do for UDP sockets. That is you simply
> RTFREE() the rtentry pointed to by the inpcb early on in udp_output()
> just to let a new one be reaquired later on. If it is NULL the code
> will simply redo the routing table lookup and store a new pointer the
> rtentry. With this every time you send a UDP packet you'll get the
> corret route. A little bit more extensive hack would simply avoid
> storing the rtentry pointer in the inpcb at all. I once did this for
> an RELENG_4 machine without any ill effects (if done correctly). The
> same applies to OpenBSD and NetBSD.
>
> --
> Andre
>
>
> > ---Mike
> >
> > At 09:59 AM 07/05/2004, Gabor wrote:
> >
> >> I am experiencing some weird routing phenomena.
> >> When I open a UDP socket and send datagrams to an address(172.30.1.1)
> >> and then remove that route(route delete 172.30.1.1) then my packets
> >> switch from going out the route specific interface(rl0) to going out
> >> the default interface(fxp0). This is as expected. Then I add back
> >> the route (route add 172.30.1.1 10.0.2.2) and the packets swing back
> >> to the route specific interface(rl0). However, if I bind my socket to
> >> a source address(172.16.24.33), when I remove the route and then add
> >> it back, the packets continue to go out the default interface(fxp0)
> >> instead of going out the route specific interface(rl0).
> >>
> >> This is on 4.9 STABLE. I was unable to reproduce this on 5.2.1. What
> >> changes have there been that haven't been MFC'ed?
> >>
> >> =0= udp-test # netstat -nr
> >> Routing tables
> >>
> >> Internet:
> >> Destination Gateway Flags Refs Use Netif
> >> Expire
> >> default 192.168.43.1 UGSc 2 2440 fxp0
> >> 10.0.2/24 link#1 UC 2 0 rl0
> >> 10.0.2.1 00:50:fc:32:52:a7 UHLW 0 2 lo0
> >> 10.0.2.2 00:0e:0c:05:09:19 UHLW 1 3
> >> rl0 69
> >> 172.0.0.1 172.0.0.1 UH 0 0 lo0
> >> 172.30.1.1 10.0.2.2 UGHS 0 0 rl0
> >> 192.168.7 link#1 UC 0 0 rl0
> >> 192.168.43 link#2 UC 4 0 fxp0
> >> 192.168.43.1 00:50:bf:33:63:70 UHLW 4 56111 fxp0
> >> 1079
> >> 192.168.43.31 link#2 UHLW 1 249 fxp0
> >> 192.168.43.157 00:a0:c9:4b:a5:f4 UHLW 6 2168880 fxp0
> >> 771
> >> 192.168.43.242 link#2 UHLW 1 718878 fxp0
> >>
> >> =0= udp-test # ifconfig
> >> rl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> >> inet 192.168.7.2 netmask 0xffffff00 broadcast 192.168.7.255
> >> inet 10.0.2.1 netmask 0xffffff00 broadcast 10.0.2.255
> >> ether 00:50:fc:32:52:a7
> >> media: Ethernet 10baseT/UTP
> >> status: active
> >> fxp0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> >> inet 192.168.43.26 netmask 0xffffff00 broadcast 192.168.43.255
> >> ether 00:01:80:3d:b4:4f
> >> media: Ethernet autoselect (100baseTX <full-duplex>)
> >> status: active
> >> ppp0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
> >> faith0: flags=8002<BROADCAST,MULTICAST> mtu 1500
> >> ds0: flags=8008<LOOPBACK,MULTICAST> mtu 65532
> >> lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 16384
> >> inet 172.16.24.33 netmask 0xffff0000
> >> inet 172.0.0.1 netmask 0xffff0000
> >> tun0: flags=8010<POINTOPOINT,MULTICAST> mtu 1500
> >>
> >> =0= udp-test # cat udp-test.c
> >> #include <sys/types.h>
> >> #include <sys/time.h>
> >> #include <sys/socket.h>
> >> #include <netinet/in.h>
> >> #include <netdb.h>
> >> #include <unistd.h>
> >> #include <stdio.h>
> >> #include <stdlib.h>
> >> #include <string.h>
> >> #include <ctype.h>
> >>
> >> int send_pkt(unsigned char *src, unsigned char *dest, unsigned short
> >> port);
> >>
> >> int
> >> main(int argc, char **argv)
> >> {
> >> unsigned a, b, c, d, a2, b2, c2, d2;
> >> unsigned port;
> >> unsigned char src[4], dest[4];
> >>
> >>
> >> if (argc != 3) {
> >> fprintf(stderr,
> >> "Usage: %s <source> <dest>:<port>\n",
> >> argv[0]);
> >> return 1;
> >> }
> >>
> >> if (sscanf(argv[1], "%u.%u.%u.%u", &a, &b, &c, &d) == 4
> >> && a < 256 && b < 256 && c < 256 && d < 256
> >> && sscanf(argv[2], "%u.%u.%u.%u:%u", &a2, &b2, &c2, &d2,
> >> &port) == 5
> >> && a2 < 256 && b2 < 256 && c2 < 256 && d2 < 256 && port <
> >> 65536) {
> >> /* OK */
> >> src[0] = a;
> >> src[1] = b;
> >> src[2] = c;
> >> src[3] = d;
> >> dest[0] = a2;
> >> dest[1] = b2;
> >> dest[2] = c2;
> >> dest[3] = d2;
> >> send_pkt(src, dest, port);
> >> }
> >> else {
> >> fprintf(stderr,
> >> "Usage: %s <source> <dest>:<port>\n",
> >> argv[0]);
> >> return 1;
> >> }
> >>
> >> return 0;
> >> }
> >>
> >> int
> >> send_pkt(unsigned char *src, unsigned char *dest, unsigned short port)
> >> {
> >> int s, len, cnt, rc, on;
> >> struct protoent *proto;
> >> struct sockaddr_in to, from;
> >> char data[1024];
> >>
> >> if (!(proto = getprotobyname("udp"))) {
> >> perror("getprotobyname");
> >> return -1;
> >> }
> >>
> >> if ((s = socket(PF_INET, SOCK_DGRAM, proto->p_proto)) < 0) {
> >> perror("socket");
> >> return -1;
> >> }
> >> on = 1;
> >>
> >> memset(&from, 0, sizeof from);
> >> from.sin_family = AF_INET;
> >> from.sin_port = htons(0);
> >> memcpy(&from.sin_addr.s_addr, src, 4);
> >> fprintf(stderr,
> >> "bind:%d\n",
> >> bind(s, (struct sockaddr*)&from, sizeof from));
> >>
> >> memset(&to, 0, sizeof to);
> >> to.sin_family = AF_INET;
> >> to.sin_port = htons(port);
> >> memcpy(&to.sin_addr.s_addr, dest, 4);
> >> len = 58;
> >> cnt = 0;
> >> while (1) {
> >> memset(data, cnt, len);
> >> rc = sendto(s, data, len, 0, (struct sockaddr*)&to, sizeof to);
> >> if (rc < 0)
> >> perror("");
> >> fprintf(stderr, "%d %d\n", rc, cnt);
> >> sleep(5);
> >> ++cnt;
> >> }
> >> close(s);
> >>
> >> return 0;
> >> }
> >>
> >> _______________________________________________
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> >
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