From 0cf6b2d89dbe6f26bb9cba470a5fda84ea1caae7 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Wed, 28 Feb 2024 22:25:03 +1100 Subject: [PATCH] inany: Provide more conveniently typed constants for special addresses Our inany_addr type is used in some places to represent either IPv4 or IPv6 addresses, and we plan to use it more widely. We don't yet provide constants of this type for special addresses (loopback and "any"). Add some of these, both the IPv4 and IPv6 variants of those addresses, but typed as union inany_addr. To avoid actually adding more things to .data we can use some macros and casting to overlay the IPv6 versions of these with the standard library's in6addr_loopback and in6addr_any. For the IPv4 versions we need to create new constant globals. For complicated historical reasons, the standard library doesn't provide constants for IPv4 loopback and any addresses as struct in_addr. It just has macros of type in_addr_t == uint32_t, which has some gotchas w.r.t. endianness. We can use some more macros to address this lack, using macros to effectively create these IPv4 constants as pieces of the inany constants above. We use this last to avoid some awkward temporary variables just used to get an address of an IPv4 loopback address. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- inany.c | 16 ++++++++++++++++ inany.h | 9 +++++++++ tcp.c | 4 ++-- udp.c | 8 +++++--- 4 files changed, 32 insertions(+), 5 deletions(-) diff --git a/inany.c b/inany.c index edf0b05..c11e2aa 100644 --- a/inany.c +++ b/inany.c @@ -16,6 +16,22 @@ #include "siphash.h" #include "inany.h" +const union inany_addr inany_loopback4 = { + .v4mapped = { + .zero = { 0 }, + .one = { 0xff, 0xff, }, + .a4 = IN4ADDR_LOOPBACK_INIT, + }, +}; + +const union inany_addr inany_any4 = { + .v4mapped = { + .zero = { 0 }, + .one = { 0xff, 0xff, }, + .a4 = IN4ADDR_ANY_INIT, + }, +}; + /** inany_ntop - Convert an IPv[46] address to text format * @src: IPv[46] address * @dst: output buffer, minimum INANY_ADDRSTRLEN bytes diff --git a/inany.h b/inany.h index be8b8da..84e82b0 100644 --- a/inany.h +++ b/inany.h @@ -32,6 +32,15 @@ static_assert(sizeof(union inany_addr) == sizeof(struct in6_addr), static_assert(_Alignof(union inany_addr) == _Alignof(uint32_t), "union inany_addr has unexpected alignment"); +#define inany_loopback6 (*(const union inany_addr *)(&in6addr_loopback)) +extern const union inany_addr inany_loopback4; + +#define inany_any6 (*(const union inany_addr *)(&in6addr_any)) +extern const union inany_addr inany_any4; + +#define in4addr_loopback (inany_loopback4.v4mapped.a4) +#define in4addr_any (inany_any4.v4mapped.a4) + /** inany_v4 - Extract IPv4 address, if present, from IPv[46] address * @addr: IPv4 or IPv6 address * diff --git a/tcp.c b/tcp.c index 7be8355..dbe787b 100644 --- a/tcp.c +++ b/tcp.c @@ -2949,12 +2949,12 @@ static void tcp_ns_sock_init4(const struct ctx *c, in_port_t port) .port = port + c->tcp.fwd_out.delta[port], .pif = PIF_SPLICE, }; - struct in_addr loopback = IN4ADDR_LOOPBACK_INIT; int s; ASSERT(c->mode == MODE_PASTA); - s = sock_l4(c, AF_INET, IPPROTO_TCP, &loopback, NULL, port, tref.u32); + s = sock_l4(c, AF_INET, IPPROTO_TCP, &in4addr_loopback, NULL, port, + tref.u32); if (s >= 0) tcp_sock_set_bufsize(c, s); else diff --git a/udp.c b/udp.c index 5b7778e..de25eb0 100644 --- a/udp.c +++ b/udp.c @@ -96,6 +96,7 @@ #include #include #include +#include #include #include #include @@ -112,6 +113,8 @@ #include "checksum.h" #include "util.h" +#include "siphash.h" +#include "inany.h" #include "passt.h" #include "tap.h" #include "pcap.h" @@ -1017,9 +1020,8 @@ int udp_sock_init(const struct ctx *c, int ns, sa_family_t af, udp_tap_map[V4][uref.port].sock = s < 0 ? -1 : s; udp_splice_init[V4][port].sock = s < 0 ? -1 : s; } else { - struct in_addr loopback = IN4ADDR_LOOPBACK_INIT; - - r4 = s = sock_l4(c, AF_INET, IPPROTO_UDP, &loopback, + r4 = s = sock_l4(c, AF_INET, IPPROTO_UDP, + &in4addr_loopback, ifname, port, uref.u32); udp_splice_ns[V4][port].sock = s < 0 ? -1 : s; }