ca69c3f196
struct tcp_conn stores an address which could be IPv6 or IPv4 using a union. We can do this without an additional tag by encoding IPv4 addresses as IPv4-mapped IPv6 addresses. This approach is useful wider than the specific place in tcp_conn, so expose a new 'union inany_addr' like this from a new inany.h. Along with that create a number of helper functions to make working with these "inany" addresses easier. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
/* SPDX-License-Identifier: AGPL-3.0-or-later
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* Copyright Red Hat
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* Author: David Gibson <david@gibson.dropbear.id.au>
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*
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* inany.h - Types and helpers for handling addresses which could be
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* IPv6 or IPv4 (encoded as IPv4-mapped IPv6 addresses)
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*/
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#include <assert.h>
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/** union inany_addr - Represents either an IPv4 or IPv6 address
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* @a6: Address as an IPv6 address, may be IPv4-mapped
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* @v4mapped.zero: All zero-bits for an IPv4 address
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* @v4mapped.one: All one-bits for an IPv4 address
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* @v4mapped.a4: If @a6 is an IPv4 mapped address, the IPv4 address
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*
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* @v4mapped shouldn't be accessed except via helpers.
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*/
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union inany_addr {
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struct in6_addr a6;
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struct {
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uint8_t zero[10];
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uint8_t one[2];
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struct in_addr a4;
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} v4mapped;
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};
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/** inany_v4 - Extract IPv4 address, if present, from IPv[46] address
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* @addr: IPv4 or IPv6 address
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*
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* Return: IPv4 address if @addr is IPv4, NULL otherwise
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*/
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static inline const struct in_addr *inany_v4(const union inany_addr *addr)
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{
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if (!IN6_IS_ADDR_V4MAPPED(&addr->a6))
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return NULL;
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return &addr->v4mapped.a4;
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}
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/** inany_equals - Compare two IPv[46] addresses
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* @a, @b: IPv[46] addresses
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*
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* Return: true if @a and @b are the same address
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*/
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static inline bool inany_equals(const union inany_addr *a,
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const union inany_addr *b)
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{
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return IN6_ARE_ADDR_EQUAL(&a->a6, &b->a6);
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}
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/** inany_from_af - Set IPv[46] address from IPv4 or IPv6 address
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* @aa: Pointer to store IPv[46] address
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* @af: Address family of @addr
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* @addr: struct in_addr (IPv4) or struct in6_addr (IPv6)
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*/
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static inline void inany_from_af(union inany_addr *aa, int af, const void *addr)
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{
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if (af == AF_INET6) {
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aa->a6 = *((struct in6_addr *)addr);
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} else if (af == AF_INET) {
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memset(&aa->v4mapped.zero, 0, sizeof(aa->v4mapped.zero));
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memset(&aa->v4mapped.one, 0xff, sizeof(aa->v4mapped.one));
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aa->v4mapped.a4 = *((struct in_addr *)addr);
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} else {
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/* Not valid to call with other address families */
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assert(0);
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}
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}
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