Re: [PATCH 2/3] icmp: Flow based error reporting

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Mar 08, 2024 at 12:26:40AM +0100, Stefano Brivio wrote:
> On Thu, 29 Feb 2024 15:15:33 +1100
> David Gibson <david@gibson.dropbear.id.au> wrote:
> 
> > Use flow_dbg() and flow_err() helpers to generate flow-linked error
> > messages in most places.  Make a few small improvements to the messages
> > while we're at it.  This allows us to avoid the awkward 'pname' variables
> > since whether we're dealing with ICMP or ICMPv6 is already built into the
> > flow type which these helpers include.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >  icmp.c | 31 ++++++++++++++-----------------
> >  1 file changed, 14 insertions(+), 17 deletions(-)
> > 
> > diff --git a/icmp.c b/icmp.c
> > index 1caf791d..63adafcf 100644
> > --- a/icmp.c
> > +++ b/icmp.c
> > @@ -61,7 +61,6 @@ void icmp_sock_handler(const struct ctx *c, sa_family_t af, union epoll_ref ref)
> >  {
> >  	struct icmp_ping_flow *pingf = af == AF_INET
> >  		? icmp_id_map[V4][ref.icmp.id] : icmp_id_map[V6][ref.icmp.id];
> > -	const char *const pname = af == AF_INET ? "ICMP" : "ICMPv6";
> >  	union sockaddr_inany sr;
> >  	socklen_t sl = sizeof(sr);
> >  	char buf[USHRT_MAX];
> > @@ -75,8 +74,7 @@ void icmp_sock_handler(const struct ctx *c, sa_family_t af, union epoll_ref ref)
> >  
> >  	n = recvfrom(ref.fd, buf, sizeof(buf), 0, &sr.sa, &sl);
> >  	if (n < 0) {
> > -		warn("%s: recvfrom() error on ping socket: %s",
> > -		     pname, strerror(errno));
> > +		flow_err(pingf, "recvfrom() error: %s", strerror(errno));
> >  		return;
> >  	}
> >  	if (sr.sa_family != af)
> > @@ -113,8 +111,9 @@ void icmp_sock_handler(const struct ctx *c, sa_family_t af, union epoll_ref ref)
> >  		pingf->seq = seq;
> >  	}
> >  
> > -	debug("%s: echo reply to tap, ID: %"PRIu16", seq: %"PRIu16, pname,
> > -	      ref.icmp.id, seq);
> > +	flow_dbg(pingf, "echo reply to tap, ID: %"PRIu16", seq: %"PRIu16,
> > +		 ref.icmp.id, seq);
> > +
> >  	if (af == AF_INET)
> >  		tap_icmp4_send(c, sr.sa4.sin_addr, tap_ip4_daddr(c), buf, n);
> >  	else if (af == AF_INET6)
> > @@ -123,7 +122,7 @@ void icmp_sock_handler(const struct ctx *c, sa_family_t af, union epoll_ref ref)
> >  	return;
> >  
> >  unexpected:
> > -	warn("%s: Unexpected packet on ping socket", pname);
> > +	flow_err(pingf, "Unexpected packet on ping socket");
> >  }
> >  
> >  /**
> > @@ -158,7 +157,6 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
> >  					    struct icmp_ping_flow **id_sock,
> >  					    sa_family_t af, uint16_t id)
> >  {
> > -	const char *const pname = af == AF_INET ? "ICMP" : "ICMPv6";
> >  	uint8_t flowtype = af == AF_INET ? FLOW_PING4 : FLOW_PING6;
> >  	union icmp_epoll_ref iref = { .id = id };
> >  	union flow *flow = flow_alloc();
> > @@ -195,9 +193,9 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
> >  	if (pingf->sock > FD_REF_MAX)
> >  		goto cancel;
> >  
> > -	*id_sock = pingf;
> > +	flow_dbg(pingf, "new socket %i for echo ID %"PRIu16, pingf->sock, id);
> >  
> > -	debug("%s: new socket %i for echo ID %"PRIu16, pname, pingf->sock, id);
> > +	*id_sock = pingf;
> >  
> >  	return pingf;
> >  
> > @@ -222,7 +220,6 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
> >  		     const void *saddr, const void *daddr,
> >  		     const struct pool *p, const struct timespec *now)
> >  {
> > -	const char *const pname = af == AF_INET ? "ICMP" : "ICMPv6";
> >  	union sockaddr_inany sa = { .sa_family = af };
> >  	const socklen_t sl = af == AF_INET ? sizeof(sa.sa4) : sizeof(sa.sa6);
> >  	struct icmp_ping_flow *pingf, **id_sock;
> > @@ -276,13 +273,13 @@ int icmp_tap_handler(const struct ctx *c, uint8_t pif, sa_family_t af,
> >  
> >  	pingf->ts = now->tv_sec;
> >  
> > -	if (sendto(pingf->sock, pkt, plen, MSG_NOSIGNAL, &sa.sa, sl) < 0) {
> > -		debug("%s: failed to relay request to socket: %s",
> > -		      pname, strerror(errno));
> > -	} else {
> > -		debug("%s: echo request to socket, ID: %"PRIu16", seq: %"PRIu16,
> > -		      pname, id, seq);
> > -	}
> > +	if (sendto(pingf->sock, pkt, plen, MSG_NOSIGNAL, &sa.sa, sl) < 0)
> > +		flow_dbg(pingf, "failed to relay request to socket: %s",
> > +			 strerror(errno));
> > +	else
> > +		flow_dbg(pingf,
> > +			 "echo request to socket, ID: %"PRIu16", seq: %"PRIu16,
> > +			 id, seq);
> 
> I can add the usual curly brackets on merge. The rest of the series
> looks good to me.

Thanks.  It may take me a minute to internalise the "braces if > 1
physical line" rule.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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