I was being annoyed by this bug today. It doesn’t happen often but I suspect
when patching the ppp daemon or ISP changes the ppp interface gets a new ID.
strace -p 294339
strace: Process 294339 attached
select(7, [4 6], NULL, NULL, {tv_sec=92, tv_usec=146932}) = 0 (Timeout)
sendto(4, “XXXXXXXXX"..., 48, 0, {sa_family=AF_INET6, sin6_port=htons(547),
sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "ff02::1:2", &sin6_addr),
sin6_scope_id=13}, 28) = -1 ENETUNREACH (Network is unreachable)
getpid() = 294339
sendto(3, "<27>Jun 13 16:15:53 dhcp6c[29433"..., 89, MSG_NOSIGNAL, NULL, 0) = 89
select(7, [4 6], NULL, NULL, {tv_sec=117, tv_usec=240413}^Cstrace: Process
294339 detached
<detached …>
I’m not 100% sure but if the sin6_scope_id=13 matched the same ID returned by
"ip a” it has definitely changed.
My current thought is when the error occurs to assume a linked problem and try
an ifreset(ifp) then retry the block:
dst.sin6_scope_id = ifp->linkid;
if (sendto(sock, buf, len, 0, (struct sockaddr *)&dst,
sysdep_sa_len((struct sockaddr *)&dst)) == -1) {
debug_printf(LOG_ERR, FNAME,
"transmit failed: %s", strerror(errno));
goto end;
}
My first task is to try and reproduce when the family won’t notice. Play for
this weekend maybe.
