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fc8f0f8c48
We have a bunch of variants of the siphash functions for different data sizes. The callers, in tcp.c, need to pack the various values they want to hash into a temporary structure, then call the appropriate version. We can avoid the copy into the temporary by directly using the incremental siphash functions. The length specific hash functions also have an undocumented constraint that the data pointer they take must, in fact, be aligned to avoid unaligned accesses, which may cause crashes on some architectures. So, prefer the incremental approach and remove the length-specific functions. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
113 lines
3.4 KiB
C
113 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0-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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#ifndef INANY_H
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#define INANY_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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* @u64: As an array of u64s (solely for hashing)
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*
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* @v4mapped and @u64 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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uint32_t u32[4];
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};
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static_assert(sizeof(union inany_addr) == sizeof(struct in6_addr));
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static_assert(_Alignof(union inany_addr) == _Alignof(uint32_t));
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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 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 (struct in_addr *)&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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/** inany_from_sockaddr - Extract IPv[46] address and port number from sockaddr
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* @aa: Pointer to store IPv[46] address
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* @port: Pointer to store port number, host order
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* @addr: struct sockaddr_in (IPv4) or struct sockaddr_in6 (IPv6)
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*/
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static inline void inany_from_sockaddr(union inany_addr *aa, in_port_t *port,
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const void *addr)
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{
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const struct sockaddr *sa = (const struct sockaddr *)addr;
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if (sa->sa_family == AF_INET6) {
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struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *)sa;
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inany_from_af(aa, AF_INET6, &sa6->sin6_addr);
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*port = ntohs(sa6->sin6_port);
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} else if (sa->sa_family == AF_INET) {
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struct sockaddr_in *sa4 = (struct sockaddr_in *)sa;
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inany_from_af(aa, AF_INET, &sa4->sin_addr);
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*port = ntohs(sa4->sin_port);
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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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/** inany_siphash_feed- Fold IPv[46] address into an in-progress siphash
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* @state: siphash state
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* @aa: inany to hash
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*/
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static inline void inany_siphash_feed(struct siphash_state *state,
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const union inany_addr *aa)
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{
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siphash_feed(state, (uint64_t)aa->u32[0] << 32 | aa->u32[1]);
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siphash_feed(state, (uint64_t)aa->u32[2] << 32 | aa->u32[3]);
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}
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#endif /* INANY_H */
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