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| author | Rich Felker <dalias@aerifal.cx> | 2025-07-30 09:32:02 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2025-07-30 09:32:02 -0400 |
| commit | a6244de1c94588cd8cc965c15619d2649418f7a3 (patch) | |
| tree | 8b2aad3e37d47ca1f9d90d2d2be6bc0e383d387f /include/netinet | |
| parent | 8fd5d031876345e42ae3d11cc07b962f8625bc3b (diff) | |
| download | musl-a6244de1c94588cd8cc965c15619d2649418f7a3.tar.gz | |
fix erroneous definition of IN6_IS_ADDR_V4COMPAT
v4-compatible addresses in ipv6 are a deprecated feature where the
high 96 bits are all zero and an ipv4 address is stored in the low
32 bits. however, since :: and ::1 are the unspecified and loopback
addresses, these two particular values are excluded from the
definition of the v4-compat class.
our version of the macro incorrectly assessed this condition by
checking only the high 96 and low 8 bits. this incorrectly excluded
the v4compat version of any ipv4 address ending in .1, not just ::1.
rather than writing out non-obvious or error-prone conditions on the
individual address bytes, just express the "not :: or ::1" condition
naturally using the existing IN6_IS_ADDR_UNSPECIFIED and
IN6_IS_ADDR_LOOPBACK macros, after checking that the high 96 bits are
all zero. any vaguely reasonable compiler will collapse out the
redundant tests of the upper bits as part of CSE.
Diffstat (limited to 'include/netinet')
| -rw-r--r-- | include/netinet/in.h | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/include/netinet/in.h b/include/netinet/in.h index fb628b61..60bbaa75 100644 --- a/include/netinet/in.h +++ b/include/netinet/in.h @@ -132,7 +132,8 @@ uint16_t ntohs(uint16_t); #define IN6_IS_ADDR_V4COMPAT(a) \ (((uint32_t *) (a))[0] == 0 && ((uint32_t *) (a))[1] == 0 && \ - ((uint32_t *) (a))[2] == 0 && ((uint8_t *) (a))[15] > 1) + ((uint32_t *) (a))[2] == 0 && \ + !IN6_IS_ADDR_UNSPECIFIED(a) && !IN6_IS_ADDR_LOOPBACK(a)) #define IN6_IS_ADDR_MC_NODELOCAL(a) \ (IN6_IS_ADDR_MULTICAST(a) && ((((uint8_t *) (a))[1] & 0xf) == 0x1)) |