On Thu, 17 Oct 2024 16:32:58 +1100
David Gibson <david(a)gibson.dropbear.id.au> wrote:
This fixes a number of harmless but slightly ugly
warts in the ARP
resolution code:
* Use in4addr_any to represent 0.0.0.0 rather than hand constructing an
example.
* When comparing am->sip against 0.0.0.0 use sizeof(am->sip) instead of
sizeof(am->tip) (same value, but makes more logical sense)
* Described the guest's assigned address as such, rather than as "our
address" - that's not usually what we mean by "our address" these
days
* Remove "we might have the same IP address" comment which I can't make
sense of in context (possibly it's relating to the statement below,
which already has its own comment?)
Right, yes, I added the part below later, in 64c0f20ab3f8 ("arp: Don't
resolve own, configured IPv4 address").
The first check comes from 2166c5872e9b ("arp: Don't answer announcements
from guest or namespace") instead. The commit title makes it obvious, the
comment not so much.
Signed-off-by: David Gibson
<david(a)gibson.dropbear.id.au>
---
arp.c | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/arp.c b/arp.c
index 53334da..d34b20e 100644
--- a/arp.c
+++ b/arp.c
@@ -59,14 +59,12 @@ int arp(const struct ctx *c, const struct pool *p)
ah->ar_op != htons(ARPOP_REQUEST))
return 1;
- /* Discard announcements (but not 0.0.0.0 "probes"): we might have the
- * same IP address, hide that.
- */
- if (memcmp(am->sip, (unsigned char[4]){ 0 }, sizeof(am->tip)) &&
+ /* Discard announcements, but not 0.0.0.0 "probes" */
+ if (memcmp(am->sip, &in4addr_any, sizeof(am->sip)) &&
!memcmp(am->sip, am->tip, sizeof(am->sip)))
return 1;
- /* Don't resolve our own address, either. */
+ /* Don't resolve guest's assigned address, either. */
Nit: "the guest's assigned address".
if
(!memcmp(am->tip, &c->ip4.addr, sizeof(am->tip)))
return 1;
--
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.