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passt/ip.h
Stefano Brivio c0fbc7ef2a dhcp: Honour broadcast flag (RFC 2131, 4.1)
It's widely considered a legacy option nowadays, and I've haven't seen
clients setting it since Windows 95, but it's convenient for a minimal
DHCP client not using raw IP sockets such as what I'm playing with for
muvm.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
2024-11-27 05:37:28 +01:00

108 lines
2.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later
* Copyright (c) 2021 Red Hat GmbH
* Author: Stefano Brivio <sbrivio@redhat.com>
*/
#ifndef IP_H
#define IP_H
#include <netinet/ip.h>
#include <netinet/ip6.h>
#define IN4_IS_ADDR_UNSPECIFIED(a) \
(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_ANY))
#define IN4_IS_ADDR_BROADCAST(a) \
(((struct in_addr *)(a))->s_addr == htonl_constant(INADDR_BROADCAST))
#define IN4_IS_ADDR_LOOPBACK(a) \
(ntohl(((struct in_addr *)(a))->s_addr) >> IN_CLASSA_NSHIFT == IN_LOOPBACKNET)
#define IN4_IS_ADDR_MULTICAST(a) \
(IN_MULTICAST(ntohl(((struct in_addr *)(a))->s_addr)))
#define IN4_ARE_ADDR_EQUAL(a, b) \
(((struct in_addr *)(a))->s_addr == ((struct in_addr *)b)->s_addr)
#define IN4ADDR_LOOPBACK_INIT \
{ .s_addr = htonl_constant(INADDR_LOOPBACK) }
#define IN4ADDR_ANY_INIT \
{ .s_addr = htonl_constant(INADDR_ANY) }
#define IN4_IS_ADDR_LINKLOCAL(a) \
((ntohl(((struct in_addr *)(a))->s_addr) >> 16) == 0xa9fe)
#define IN4_IS_PREFIX_LINKLOCAL(a, len) \
((len) >= 16 && IN4_IS_ADDR_LINKLOCAL(a))
#define L2_BUF_IP4_INIT(proto) \
{ \
.version = 4, \
.ihl = 5, \
.tos = 0, \
.tot_len = 0, \
.id = 0, \
.frag_off = 0, \
.ttl = 0xff, \
.protocol = (proto), \
.saddr = 0, \
.daddr = 0, \
}
#define L2_BUF_IP4_PSUM(proto) ((uint32_t)htons_constant(0x4500) + \
(uint32_t)htons(0xff00 | (proto)))
#define IN6_IS_PREFIX_LINKLOCAL(a, len) \
((len) >= 10 && IN6_IS_ADDR_LINKLOCAL(a))
#define L2_BUF_IP6_INIT(proto) \
{ \
.priority = 0, \
.version = 6, \
.flow_lbl = { 0 }, \
.payload_len = 0, \
.nexthdr = (proto), \
.hop_limit = 255, \
.saddr = IN6ADDR_ANY_INIT, \
.daddr = IN6ADDR_ANY_INIT, \
}
struct ipv6hdr {
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpedantic"
#if __BYTE_ORDER == __BIG_ENDIAN
uint8_t version:4,
priority:4;
#else
uint8_t priority:4,
version:4;
#endif
#pragma GCC diagnostic pop
uint8_t flow_lbl[3];
uint16_t payload_len;
uint8_t nexthdr;
uint8_t hop_limit;
struct in6_addr saddr;
struct in6_addr daddr;
};
struct ipv6_opt_hdr {
uint8_t nexthdr;
uint8_t hdrlen;
/*
* TLV encoded option data follows.
*/
} __attribute__((packed)); /* required for some archs */
char *ipv6_l4hdr(const struct pool *p, int idx, size_t offset, uint8_t *proto,
size_t *dlen);
/* IPv6 link-local all-nodes multicast adddress, ff02::1 */
static const struct in6_addr in6addr_ll_all_nodes = {
.s6_addr = {
0xff, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01,
},
};
/* IPv4 Limited Broadcast (RFC 919, Section 7), 255.255.255.255 */
static const struct in_addr in4addr_broadcast = { 0xffffffff };
#endif /* IP_H */