Re: [PATCH v3 06/14] ip: Add ipproto_name() function

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

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On Thu, Jan 08, 2026 at 02:22:21PM +0100, Laurent Vivier wrote:
> On 1/8/26 03:29, David Gibson wrote:
> > Add a function to get the name of an IP protocol from its number.  Usually
> > this would be done by getprotobynumber(), but that requires access to
> > /etc/protocols and might allocate.  We can't do either of those once we've
> > self-isolated.
> > 
> > Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> > ---
> >   ip.c | 27 +++++++++++++++++++++++++++
> >   ip.h |  2 ++
> >   2 files changed, 29 insertions(+)
> > 
> > diff --git a/ip.c b/ip.c
> > index 9a7f4c54..f1d224bd 100644
> > --- a/ip.c
> > +++ b/ip.c
> > @@ -67,3 +67,30 @@ found:
> >   	*proto = nh;
> >   	return true;
> >   }
> > +
> > +/**
> > + * ipproto_name() - Get IP protocol name from number
> > + * @proto:	IP protocol number
> > + *
> > + * Return: pointer to name of protocol @proto
> > + *
> > + * Usually this would be done with getprotobynumber(3) but that reads
> > + * /etc/protocols and might allocate, which isn't possible for us once
> > + * self-isolated.
> > + */
> > +/* cppcheck-suppress unusedFunction */
> > +const char *ipproto_name(uint8_t proto)
> > +{
> > +	switch (proto) {
> > +	case IPPROTO_ICMP:
> > +		return "ICMP";
> > +	case IPPROTO_TCP:
> > +		return "TCP";
> > +	case IPPROTO_UDP:
> > +		return "UDP";
> > +	case IPPROTO_ICMPV6:
> > +		return "ICMPv6";
> > +	default:
> > +		return "<unknown protocol>";
> > +	}
> > +}
> > diff --git a/ip.h b/ip.h
> > index 5830b923..42b417c5 100644
> > --- a/ip.h
> > +++ b/ip.h
> > @@ -116,6 +116,7 @@ static inline uint32_t ip6_get_flow_lbl(const struct ipv6hdr *ip6h)
> >   }
> >   bool ipv6_l4hdr(struct iov_tail *data, uint8_t *proto, size_t *dlen);
> > +const char *ipproto_name(uint8_t proto);
> >   /* IPv6 link-local all-nodes multicast address, ff02::1 */
> >   static const struct in6_addr in6addr_ll_all_nodes = {
> > @@ -135,4 +136,5 @@ static const struct in_addr in4addr_broadcast = { 0xffffffff };
> >   #define IPV6_MIN_MTU		1280
> >   #endif
> > +
> 
> Extra blank line

Oops, fixed.

> >   #endif /* IP_H */
> 
> Reviewed-by: Laurent Vivier <lvivier@redhat.com>
> 

-- 
David Gibson (he or they)	| 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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