Em 16-11-2011 17:48, Dale Dellutri escreveu:

I have an ethernet device in my lan with a primary address 192.168.5.205 and a secondary address .217. I added the secondary address after network startup established the primary address by an ip addr add command:

# ip addr add 192.168.5.217/24 broadcast 192.168.5.255 dev eth0

# ip addr show ... 2: eth0:<BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000 link/ether 78:2b:cb:23:21:4c brd ff:ff:ff:ff:ff:ff inet 192.168.5.205/24 brd 192.168.5.255 scope global eth0 inet 192.168.5.217/24 brd 192.168.5.255 scope global secondary eth0 inet6 fe80::7a2b:cbff:fe23:214c/64 scope link valid_lft forever preferred_lft forever ...

Then I add a new route via a network gateway but I want the route to use the secondary address as a source.

# ip route add 11.11.11.11 via 192.168.5.148 src 192.168.5.217

And the ip route show command shows that it knows the source.

# ip route show 11.11.11.11 via 192.168.5.148 dev eth0 src 192.168.5.217

But where is the source address kept? If I look at /proc/net/route, it shows the route (0B0B0B0B = 11.11.11.11), but not the source address.

# cat /proc/net/route Iface Destination Gateway Flags RefCnt Use Metric Mask MTU Window IRTT eth0 0B0B0B0B 9405A8C0 0007 0 0 0 FFFFFFFF 0 0 0 ...

Where is the source address kept?

ip route uses NETLINK to obtain info

I did: strace -o /tmp/strace.out ip route show

and inside strace.out: bind(3, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 0 sendto(3, "\24\0\0\0\22\0\1\0031\25\304N\0\0\0\0\0\0\0\0", 20, 0, {sa_family=AF_NETLINK, pid=0, groups=00000000}, 12) = 20 recvmsg(3, {msg_name(12)={sa_family=AF_NETLINK, pid=0, groups=00000000}, msg_iov(1)=[{"\364\0\0\0\20\0\2\0001\25\304N"\r\0\0\0\0\4\3\1\0\0\0I\0\1\0\0\0\0\0"..., 16384}], msg_controllen=0, msg_flags=0}, 0) = 1688

You can see /proc/net/rt_cache, there is a Source column there.