networking/udhcp/common.h

   1 /* vi: set sw=4 ts=4: */
   2 /* common.h
   3  *
   4  * Russ Dill <Russ.Dill@asu.edu> September 2001
   5  * Rewritten by Vladimir Oleynik <dzo@simtreas.ru> (C) 2003
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
   8  */
   9 #ifndef UDHCP_COMMON_H
  10 #define UDHCP_COMMON_H 1
  11
  12 #include "libbb.h"
  13 #include <netinet/udp.h>
  14 #include <netinet/ip.h>
  15
  16 PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN
  17
  18 #define DEFAULT_SCRIPT   CONFIG_UDHCPC_DEFAULT_SCRIPT
  19
  20 extern const uint8_t MAC_BCAST_ADDR[6]; /* six all-ones */
  21
  22 /*** packet.h ***/
  23
  24 /* DHCP protocol. See RFC 2131 */
  25 #define DHCP_MAGIC              0x63825363
  26
  27 #define DHCP_OPTIONS_BUFSIZE    308
  28
  29 #define BOOTREQUEST             1
  30 #define BOOTREPLY               2
  31
  32 //TODO: rename ciaddr/yiaddr/chaddr
  33 struct dhcp_packet {
  34         uint8_t op;      /* BOOTREQUEST or BOOTREPLY */
  35         uint8_t htype;   /* hardware address type. 1 = 10mb ethernet */
  36         uint8_t hlen;    /* hardware address length */
  37         uint8_t hops;    /* used by relay agents only */
  38         uint32_t xid;    /* unique id */
  39         uint16_t secs;   /* elapsed since client began acquisition/renewal */
  40         uint16_t flags;  /* only one flag so far: */
  41 #define BROADCAST_FLAG 0x8000 /* "I need broadcast replies" */
  42         uint32_t ciaddr; /* client IP (if client is in BOUND, RENEW or REBINDING state) */
  43         uint32_t yiaddr; /* 'your' (client) IP address */
  44         /* IP address of next server to use in bootstrap, returned in DHCPOFFER, DHCPACK by server */
  45         uint32_t siaddr_nip;
  46         uint32_t gateway_nip; /* relay agent IP address */
  47         uint8_t chaddr[16];   /* link-layer client hardware address (MAC) */
  48         uint8_t sname[64];    /* server host name (ASCIZ) */
  49         uint8_t file[128];    /* boot file name (ASCIZ) */
  50         uint32_t cookie;      /* fixed first four option bytes (99,130,83,99 dec) */
  51         uint8_t options[DHCP_OPTIONS_BUFSIZE + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS];
  52 } PACKED;
  53 #define DHCP_PKT_SNAME_LEN      64
  54 #define DHCP_PKT_FILE_LEN      128
  55 #define DHCP_PKT_SNAME_LEN_STR "64"
  56 #define DHCP_PKT_FILE_LEN_STR "128"
  57
  58 struct ip_udp_dhcp_packet {
  59         struct iphdr ip;
  60         struct udphdr udp;
  61         struct dhcp_packet data;
  62 } PACKED;
  63
  64 /* Let's see whether compiler understood us right */
  65 struct BUG_bad_sizeof_struct_ip_udp_dhcp_packet {
  66         char BUG_bad_sizeof_struct_ip_udp_dhcp_packet
  67                 [(sizeof(struct ip_udp_dhcp_packet) != 576 + CONFIG_UDHCPC_SLACK_FOR_BUGGY_SERVERS) ? -1 : 1];
  68 };
  69
  70 // RFC 2131  Table 5: Fields and options used by DHCP clients
  71 //
  72 // Field      DHCPDISCOVER          DHCPREQUEST           DHCPDECLINE,
  73 //            DHCPINFORM                                  DHCPRELEASE
  74 // -----      ------------          -----------           -----------
  75 // 'op'       BOOTREQUEST           BOOTREQUEST           BOOTREQUEST
  76 // 'hops'     0                     0                     0
  77 // 'xid'      selected by client    'xid' from server     selected by
  78 //                                  DHCPOFFER message     client
  79 // 'secs'     0 or seconds since    0 or seconds since    0
  80 //            DHCP process started  DHCP process started
  81 // 'flags'    Set 'BROADCAST'       Set 'BROADCAST'       0
  82 //            flag if client        flag if client
  83 //            requires broadcast    requires broadcast
  84 //            reply                 reply
  85 // 'ciaddr'   0 (DHCPDISCOVER)      0 or client's         0 (DHCPDECLINE)
  86 //            client's              network address       client's network
  87 //            network address       (BOUND/RENEW/REBIND)  address
  88 //            (DHCPINFORM)                                (DHCPRELEASE)
  89 // 'yiaddr'   0                     0                     0
  90 // 'siaddr'   0                     0                     0
  91 // 'giaddr'   0                     0                     0
  92 // 'chaddr'   client's hardware     client's hardware     client's hardware
  93 //            address               address               address
  94 // 'sname'    options, if           options, if           (unused)
  95 //            indicated in          indicated in
  96 //            'sname/file'          'sname/file'
  97 //            option; otherwise     option; otherwise
  98 //            unused                unused
  99 // 'file'     options, if           options, if           (unused)
 100 //            indicated in          indicated in
 101 //            'sname/file'          'sname/file'
 102 //            option; otherwise     option; otherwise
 103 //            unused                unused
 104 // 'options'  options               options               (unused)
 105 //
 106 // Option                     DHCPDISCOVER  DHCPREQUEST      DHCPDECLINE,
 107 //                            DHCPINFORM                     DHCPRELEASE
 108 // ------                     ------------  -----------      -----------
 109 // Requested IP address       MAY           MUST (in         MUST
 110 //                            (DISCOVER)    SELECTING or     (DHCPDECLINE),
 111 //                            MUST NOT      INIT-REBOOT)     MUST NOT
 112 //                            (INFORM)      MUST NOT (in     (DHCPRELEASE)
 113 //                                          BOUND or
 114 //                                          RENEWING)
 115 // IP address lease time      MAY           MAY              MUST NOT
 116 //                            (DISCOVER)
 117 //                            MUST NOT
 118 //                            (INFORM)
 119 // Use 'file'/'sname' fields  MAY           MAY              MAY
 120 // Client identifier          MAY           MAY              MAY
 121 // Vendor class identifier    MAY           MAY              MUST NOT
 122 // Server identifier          MUST NOT      MUST (after      MUST
 123 //                                          SELECTING)
 124 //                                          MUST NOT (after
 125 //                                          INIT-REBOOT,
 126 //                                          BOUND, RENEWING
 127 //                                          or REBINDING)
 128 // Parameter request list     MAY           MAY              MUST NOT
 129 // Maximum message size       MAY           MAY              MUST NOT
 130 // Message                    SHOULD NOT    SHOULD NOT       SHOULD
 131 // Site-specific              MAY           MAY              MUST NOT
 132 // All others                 MAY           MAY              MUST NOT
 133
 134
 135 uint16_t udhcp_checksum(void *addr, int count) FAST_FUNC;
 136
 137 void udhcp_init_header(struct dhcp_packet *packet, char type) FAST_FUNC;
 138
 139 /*int udhcp_recv_raw_packet(struct dhcp_packet *dhcp_pkt, int fd); - in dhcpc.h */
 140 int udhcp_recv_kernel_packet(struct dhcp_packet *packet, int fd) FAST_FUNC;
 141
 142 int udhcp_send_raw_packet(struct dhcp_packet *dhcp_pkt,
 143                 uint32_t source_ip, int source_port,
 144                 uint32_t dest_ip, int dest_port, const uint8_t *dest_arp,
 145                 int ifindex) FAST_FUNC;
 146
 147 int udhcp_send_kernel_packet(struct dhcp_packet *dhcp_pkt,
 148                 uint32_t source_ip, int source_port,
 149                 uint32_t dest_ip, int dest_port) FAST_FUNC;
 150
 151
 152 /**/
 153
 154 void udhcp_run_script(struct dhcp_packet *packet, const char *name) FAST_FUNC;
 155
 156 // Still need to clean these up...
 157
 158 /* from options.h */
 159 #define get_option              udhcp_get_option
 160 #define end_option              udhcp_end_option
 161 #define add_option_string       udhcp_add_option_string
 162 #define add_simple_option       udhcp_add_simple_option
 163
 164 void udhcp_sp_setup(void) FAST_FUNC;
 165 int udhcp_sp_fd_set(fd_set *rfds, int extra_fd) FAST_FUNC;
 166 int udhcp_sp_read(const fd_set *rfds) FAST_FUNC;
 167 int udhcp_read_interface(const char *interface, int *ifindex, uint32_t *nip, uint8_t *mac) FAST_FUNC;
 168 int udhcp_raw_socket(int ifindex) FAST_FUNC;
 169 int udhcp_listen_socket(/*uint32_t ip,*/ int port, const char *inf) FAST_FUNC;
 170 /* Returns 1 if no reply received */
 171 int arpping(uint32_t test_nip,
 172                 const uint8_t *safe_mac,
 173                 uint32_t from_ip,
 174                 uint8_t *from_mac,
 175                 const char *interface) FAST_FUNC;
 176
 177 #if defined CONFIG_UDHCP_DEBUG && CONFIG_UDHCP_DEBUG >= 1
 178 extern unsigned dhcp_verbose;
 179 # define log1(...) do { if (dhcp_verbose >= 1) bb_info_msg(__VA_ARGS__); } while (0)
 180 # if CONFIG_UDHCP_DEBUG >= 2
 181 void udhcp_dump_packet(struct dhcp_packet *packet) FAST_FUNC;
 182 #  define log2(...) do { if (dhcp_verbose >= 2) bb_info_msg(__VA_ARGS__); } while (0)
 183 # else
 184 #  define udhcp_dump_packet(...) ((void)0)
 185 #  define log2(...) ((void)0)
 186 # endif
 187 # if CONFIG_UDHCP_DEBUG >= 3
 188 #  define log3(...) do { if (dhcp_verbose >= 3) bb_info_msg(__VA_ARGS__); } while (0)
 189 # else
 190 #  define log3(...) ((void)0)
 191 # endif
 192 #else
 193 # define udhcp_dump_packet(...) ((void)0)
 194 # define log1(...) ((void)0)
 195 # define log2(...) ((void)0)
 196 # define log3(...) ((void)0)
 197 #endif
 198
 199 POP_SAVED_FUNCTION_VISIBILITY
 200
 201 #endif