path: root/lib/packets.h

/*
 * Copyright (c) 2008, 2009 Nicira Networks.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#ifndef PACKETS_H
#define PACKETS_H 1

#include <stdint.h>
#include <string.h>
#include "compiler.h"
#include "random.h"
#include "util.h"

#define ETH_ADDR_LEN           6

static const uint8_t eth_addr_broadcast[ETH_ADDR_LEN] UNUSED
    = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };

static inline bool eth_addr_is_broadcast(const uint8_t ea[6])
{
    return (ea[0] & ea[1] & ea[2] & ea[3] & ea[4] & ea[5]) == 0xff;
}

/* Returns true if 'ea' is an Ethernet address used for virtual interfaces
 * under XenServer.  Generally the actual Ethernet address is FE:FF:FF:FF:FF:FF
 * but it can be FE:FE:FE:FE:FE:FE in some cases. */
static inline bool eth_addr_is_vif(const uint8_t ea[6])
{
    return ea[0] == 0xfe && (ea[1] & ea[2] & ea[3] & ea[4] & ea[5]) >= 0xfe;
}

static inline bool eth_addr_is_multicast(const uint8_t ea[6])
{
    return ea[0] & 1;
}
static inline bool eth_addr_is_local(const uint8_t ea[6]) 
{
    return ea[0] & 2;
}
static inline bool eth_addr_is_zero(const uint8_t ea[6]) 
{
    return !(ea[0] | ea[1] | ea[2] | ea[3] | ea[4] | ea[5]);
}
static inline bool eth_addr_equals(const uint8_t a[ETH_ADDR_LEN],
                                   const uint8_t b[ETH_ADDR_LEN]) 
{
    return !memcmp(a, b, ETH_ADDR_LEN);
}
static inline uint64_t eth_addr_to_uint64(const uint8_t ea[ETH_ADDR_LEN])
{
    return (((uint64_t) ea[0] << 40)
            | ((uint64_t) ea[1] << 32)
            | ((uint64_t) ea[2] << 24)
            | ((uint64_t) ea[3] << 16)
            | ((uint64_t) ea[4] << 8)
            | ea[5]);
}
static inline void eth_addr_from_uint64(uint64_t x, uint8_t ea[ETH_ADDR_LEN])
{
    ea[0] = x >> 40;
    ea[1] = x >> 32;
    ea[2] = x >> 24;
    ea[3] = x >> 16;
    ea[4] = x >> 8;
    ea[5] = x;
}
static inline void eth_addr_mark_random(uint8_t ea[ETH_ADDR_LEN])
{
    ea[0] &= ~1;                /* Unicast. */
    ea[0] |= 2;                 /* Private. */
}
static inline void eth_addr_random(uint8_t ea[ETH_ADDR_LEN])
{
    random_bytes(ea, ETH_ADDR_LEN);
    eth_addr_mark_random(ea);
}
/* Returns true if 'ea' is a reserved multicast address, that a bridge must
 * never forward, false otherwise. */
static inline bool eth_addr_is_reserved(const uint8_t ea[ETH_ADDR_LEN])
{
    return (ea[0] == 0x01
            && ea[1] == 0x80
            && ea[2] == 0xc2
            && ea[3] == 0x00
            && ea[4] == 0x00
            && (ea[5] & 0xf0) == 0x00);
}

#define ETH_ADDR_FMT                                                    \
    "%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8":%02"PRIx8
#define ETH_ADDR_ARGS(ea)                                   \
    (ea)[0], (ea)[1], (ea)[2], (ea)[3], (ea)[4], (ea)[5]

#define ETH_TYPE_IP            0x0800
#define ETH_TYPE_ARP           0x0806
#define ETH_TYPE_VLAN          0x8100

#define ETH_HEADER_LEN 14
#define ETH_PAYLOAD_MIN 46
#define ETH_PAYLOAD_MAX 1500
#define ETH_TOTAL_MIN (ETH_HEADER_LEN + ETH_PAYLOAD_MIN)
#define ETH_TOTAL_MAX (ETH_HEADER_LEN + ETH_PAYLOAD_MAX)
#define ETH_VLAN_TOTAL_MAX (ETH_HEADER_LEN + VLAN_HEADER_LEN + ETH_PAYLOAD_MAX)
struct eth_header {
    uint8_t eth_dst[ETH_ADDR_LEN];
    uint8_t eth_src[ETH_ADDR_LEN];
    uint16_t eth_type;
} __attribute__((packed));
BUILD_ASSERT_DECL(ETH_HEADER_LEN == sizeof(struct eth_header));

#define LLC_DSAP_SNAP 0xaa
#define LLC_SSAP_SNAP 0xaa
#define LLC_CNTL_SNAP 3

#define LLC_HEADER_LEN 3
struct llc_header {
    uint8_t llc_dsap;
    uint8_t llc_ssap;
    uint8_t llc_cntl;
} __attribute__((packed));
BUILD_ASSERT_DECL(LLC_HEADER_LEN == sizeof(struct llc_header));

#define SNAP_ORG_ETHERNET "\0\0" /* The compiler adds a null byte, so
                                    sizeof(SNAP_ORG_ETHERNET) == 3. */
#define SNAP_HEADER_LEN 5
struct snap_header {
    uint8_t snap_org[3];
    uint16_t snap_type;
} __attribute__((packed));
BUILD_ASSERT_DECL(SNAP_HEADER_LEN == sizeof(struct snap_header));

#define LLC_SNAP_HEADER_LEN (LLC_HEADER_LEN + SNAP_HEADER_LEN)
struct llc_snap_header {
    struct llc_header llc;
    struct snap_header snap;
} __attribute__((packed));
BUILD_ASSERT_DECL(LLC_SNAP_HEADER_LEN == sizeof(struct llc_snap_header));

#define VLAN_VID_MASK 0x0fff
#define VLAN_PCP_MASK 0xe000

#define VLAN_HEADER_LEN 4
struct vlan_header {
    uint16_t vlan_tci;          /* Lowest 12 bits are VLAN ID. */
    uint16_t vlan_next_type;
};
BUILD_ASSERT_DECL(VLAN_HEADER_LEN == sizeof(struct vlan_header));

#define VLAN_ETH_HEADER_LEN (ETH_HEADER_LEN + VLAN_HEADER_LEN)
struct vlan_eth_header {
    uint8_t veth_dst[ETH_ADDR_LEN];
    uint8_t veth_src[ETH_ADDR_LEN];
    uint16_t veth_type;         /* Always htons(ETH_TYPE_VLAN). */
    uint16_t veth_tci;          /* Lowest 12 bits are VLAN ID. */
    uint16_t veth_next_type;
} __attribute__((packed));
BUILD_ASSERT_DECL(VLAN_ETH_HEADER_LEN == sizeof(struct vlan_eth_header));

/* The "(void) (ip)[0]" below has no effect on the value, since it's the first
 * argument of a comma expression, but it makes sure that 'ip' is a pointer.
 * This is useful since a common mistake is to pass an integer instead of a
 * pointer to IP_ARGS. */
#define IP_FMT "%"PRIu8".%"PRIu8".%"PRIu8".%"PRIu8
#define IP_ARGS(ip)                             \
        ((void) (ip)[0], ((uint8_t *) ip)[0]),  \
        ((uint8_t *) ip)[1],                    \
        ((uint8_t *) ip)[2],                    \
        ((uint8_t *) ip)[3]

#define IP_VER(ip_ihl_ver) ((ip_ihl_ver) >> 4)
#define IP_IHL(ip_ihl_ver) ((ip_ihl_ver) & 15)
#define IP_IHL_VER(ihl, ver) (((ver) << 4) | (ihl))

#define IP_TYPE_ICMP 1
#define IP_TYPE_TCP 6
#define IP_TYPE_UDP 17

#define IP_VERSION 4

#define IP_DONT_FRAGMENT  0x4000 /* Don't fragment. */
#define IP_MORE_FRAGMENTS 0x2000 /* More fragments. */
#define IP_FRAG_OFF_MASK  0x1fff /* Fragment offset. */
#define IP_IS_FRAGMENT(ip_frag_off) \
        ((ip_frag_off) & htons(IP_MORE_FRAGMENTS | IP_FRAG_OFF_MASK))

#define IP_HEADER_LEN 20
struct ip_header {
    uint8_t ip_ihl_ver;
    uint8_t ip_tos;
    uint16_t ip_tot_len;
    uint16_t ip_id;
    uint16_t ip_frag_off;
    uint8_t ip_ttl;
    uint8_t ip_proto;
    uint16_t ip_csum;
    uint32_t ip_src;
    uint32_t ip_dst;
};
BUILD_ASSERT_DECL(IP_HEADER_LEN == sizeof(struct ip_header));

#define ICMP_HEADER_LEN 4
struct icmp_header {
    uint8_t icmp_type;
    uint8_t icmp_code;
    uint16_t icmp_csum;
};
BUILD_ASSERT_DECL(ICMP_HEADER_LEN == sizeof(struct icmp_header));

#define UDP_HEADER_LEN 8
struct udp_header {
    uint16_t udp_src;
    uint16_t udp_dst;
    uint16_t udp_len;
    uint16_t udp_csum;
};
BUILD_ASSERT_DECL(UDP_HEADER_LEN == sizeof(struct udp_header));

#define TCP_FIN 0x01
#define TCP_SYN 0x02
#define TCP_RST 0x04
#define TCP_PSH 0x08
#define TCP_ACK 0x10
#define TCP_URG 0x20

#define TCP_FLAGS(tcp_ctl) (htons(tcp_ctl) & 0x003f)
#define TCP_OFFSET(tcp_ctl) (htons(tcp_ctl) >> 12)

#define TCP_HEADER_LEN 20
struct tcp_header {
    uint16_t tcp_src;
    uint16_t tcp_dst;
    uint32_t tcp_seq;
    uint32_t tcp_ack;
    uint16_t tcp_ctl;
    uint16_t tcp_winsz;
    uint16_t tcp_csum;
    uint16_t tcp_urg;
};
BUILD_ASSERT_DECL(TCP_HEADER_LEN == sizeof(struct tcp_header));

#define ARP_HRD_ETHERNET 1
#define ARP_PRO_IP 0x0800
#define ARP_OP_REQUEST 1
#define ARP_OP_REPLY 2

#define ARP_ETH_HEADER_LEN 28
struct arp_eth_header {
    /* Generic members. */
    uint16_t ar_hrd;           /* Hardware type. */
    uint16_t ar_pro;           /* Protocol type. */
    uint8_t ar_hln;            /* Hardware address length. */
    uint8_t ar_pln;            /* Protocol address length. */
    uint16_t ar_op;            /* Opcode. */

    /* Ethernet+IPv4 specific members. */
    uint8_t ar_sha[ETH_ADDR_LEN]; /* Sender hardware address. */
    uint32_t ar_spa;           /* Sender protocol address. */
    uint8_t ar_tha[ETH_ADDR_LEN]; /* Target hardware address. */
    uint32_t ar_tpa;           /* Target protocol address. */
} __attribute__((packed));
BUILD_ASSERT_DECL(ARP_ETH_HEADER_LEN == sizeof(struct arp_eth_header));

#endif /* packets.h */