lib/dhcp.h

   1 /*
   2  * Copyright (c) 2008 Nicira Networks.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at:
   7  *
   8  *     http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef DHCP_H
  18 #define DHCP_H 1
  19
  20 #include <stdint.h>
  21 #include "packets.h"
  22 #include "util.h"
  23
  24 struct ds;
  25 struct ofpbuf;
  26
  27 /* Ports used by DHCP. */
  28 #define DHCP_SERVER_PORT        67       /* Port used by DHCP server. */
  29 #define DHCP_CLIENT_PORT        68       /* Port used by DHCP client. */
  30
  31 /* Values for 'op' field. */
  32 #define DHCP_BOOTREQUEST        1        /* Message sent by DHCP client. */
  33 #define DHCP_BOOTREPLY          2        /* Message sent by DHCP server. */
  34
  35 /* Bits in 'flags' field. */
  36 #define DHCP_FLAGS_BROADCAST    0x8000 /* Server must broadcast all replies. */
  37 #define DHCP_FLAGS_MBZ          0x7fff /* Must be zero. */
  38
  39 /* First four bytes of 'options' field. */
  40 #define DHCP_OPTS_COOKIE 0x63825363
  41
  42 #define DHCP_HEADER_LEN 236
  43 struct dhcp_header {
  44     uint8_t op;                 /* DHCP_BOOTREQUEST or DHCP_BOOTREPLY. */
  45     uint8_t htype;              /* ARP_HRD_ETHERNET (typically). */
  46     uint8_t hlen;               /* ETH_ADDR_LEN (typically). */
  47     uint8_t hops;               /* Hop count; set to 0 by client. */
  48     uint32_t xid;               /* Transaction ID. */
  49     uint16_t secs;              /* Since client started address acquisition. */
  50     uint16_t flags;             /* DHCP_FLAGS_*. */
  51     uint32_t ciaddr;            /* Client IP, if it has a lease for one. */
  52     uint32_t yiaddr;            /* Client ("your") IP address. */
  53     uint32_t siaddr;            /* Next server IP address. */
  54     uint32_t giaddr;            /* Relay agent IP address. */
  55     uint8_t chaddr[16];         /* Client hardware address. */
  56     char sname[64];             /* Optional server host name. */
  57     char file[128];             /* Boot file name. */
  58     /* Followed by variable-length options field. */
  59 };
  60 BUILD_ASSERT_DECL(DHCP_HEADER_LEN == sizeof(struct dhcp_header));
  61
  62 #define DHCP_ARGS                                                             \
  63     DHCP_ARG(FIXED, 0)          /* Fixed-length option (PAD and END only). */ \
  64     DHCP_ARG(IP, 4)             /* IP addresses. */                           \
  65     DHCP_ARG(SECS, 4)           /* 32-bit duration in seconds. */             \
  66     DHCP_ARG(STRING, 1)         /* NVT string, optionally null-terminated. */ \
  67     DHCP_ARG(UINT8, 1)          /* 8-bit unsigned integer. */                 \
  68     DHCP_ARG(UINT16, 2)         /* 16-bit unsigned integer. */                \
  69     DHCP_ARG(UINT32, 4)         /* 32-bit unsigned integer. */                \
  70     DHCP_ARG(BOOLEAN, 1)        /* Boolean octet (0 or 1). */
  71
  72 /* DHCP option argument types. */
  73 enum dhcp_arg_type {
  74 #define DHCP_ARG(NAME, SIZE) DHCP_ARG_##NAME,
  75     DHCP_ARGS
  76 #undef DHCP_ARG
  77 };
  78
  79 #define DHCP_MSGS                                                             \
  80     DHCP_MSG(DHCPDISCOVER, 1)   /* Client->server: What IPs are available? */ \
  81     DHCP_MSG(DHCPOFFER, 2)      /* Server->client: This IP is available. */   \
  82     DHCP_MSG(DHCPREQUEST, 3)    /* Client->server: I want that IP. */         \
  83     DHCP_MSG(DHCPDECLINE, 4)    /* Client->server: That IP is in use!. */     \
  84     DHCP_MSG(DHCPACK, 5)        /* Server->client: You can have that IP. */   \
  85     DHCP_MSG(DHCPNAK, 6)        /* Server->client: You can't have that IP. */ \
  86     DHCP_MSG(DHCPRELEASE, 7)    /* Client->server: I'm done with this IP. */  \
  87     DHCP_MSG(DCHPINFORM, 8)     /* Client->server: I'm using this IP. */
  88
  89 /* DHCP message type (this is the argument for the DHCP_MSG_TYPE option). */
  90 enum dhcp_msg_type {
  91 #define DHCP_MSG(NAME, VALUE) NAME = VALUE,
  92     DHCP_MSGS
  93 #undef DHCP_MSG
  94 };
  95 const char *dhcp_type_name(enum dhcp_msg_type);
  96
  97 /* DHCP allows for 256 standardized options and 256 vendor-specific options.
  98  * We put them in a single array, with the standard options at the
  99  * beginning. */
 100 #define DHCP_N_OPTIONS          512
 101 #define DHCP_VENDOR_OFS         256
 102
 103 /* DHCP options. */
 104 #define DHCP_OPTS                                                       \
 105     /*                                        arg   min  max         */ \
 106     /*          name                    code  type  args args        */ \
 107     DHCP_OPT(PAD,                       0, FIXED,   0, 0)               \
 108     DHCP_OPT(END,                     255, FIXED,   0, 0)               \
 109     DHCP_OPT(SUBNET_MASK,               1, IP,      1, 1)               \
 110     DHCP_OPT(TIME_OFFSET,               2, SECS,    1, 1)               \
 111     DHCP_OPT(ROUTER,                    3, IP,      1, SIZE_MAX)        \
 112     /* Time Server Option is obsolete. */                               \
 113     /* Name Server Option is obsolete. */                               \
 114     DHCP_OPT(DNS_SERVER,                6, IP,      1, SIZE_MAX)        \
 115     /* Log Server Option is obsolete. */                                \
 116     /* Cookie Server Option is obsolete. */                             \
 117     DHCP_OPT(LPR_SERVER,                9, IP,      1, SIZE_MAX)        \
 118     /* Impress Server Option is obsolete. */                            \
 119     /* Resource Location Server Option is obsolete. */                  \
 120     DHCP_OPT(HOST_NAME,                12, STRING,  1, SIZE_MAX)        \
 121     DHCP_OPT(BOOT_FILE_SIZE,           13, UINT16,  1, 1)               \
 122     /* Merit Dump File option is obsolete. */                           \
 123     DHCP_OPT(DOMAIN_NAME,              15, STRING,  1, SIZE_MAX)        \
 124     /* Swap Server option is obsolete. */                               \
 125     DHCP_OPT(ROOT_PATH,                17, STRING,  1, SIZE_MAX)        \
 126     DHCP_OPT(EXTENSIONS_PATH,          18, STRING,  1, SIZE_MAX)        \
 127     DHCP_OPT(IP_FORWARDING,            19, BOOLEAN, 1, 1)               \
 128     DHCP_OPT(SOURCE_ROUTING,           20, BOOLEAN, 1, 1)               \
 129     DHCP_OPT(POLICY_FILTER,            21, IP,      2, SIZE_MAX)        \
 130     DHCP_OPT(MAX_DGRAM_REASSEMBLY,     22, UINT16,  1, 1)               \
 131     DHCP_OPT(IP_TTL,                   23, UINT8,   1, 1)               \
 132     DHCP_OPT(PATH_MTU_TIMEOUT,         24, SECS,    1, 1)               \
 133     DHCP_OPT(PATH_MTU_PLATEAU,         25, UINT16,  2, SIZE_MAX)        \
 134     DHCP_OPT(MTU,                      26, UINT16,  1, 1)               \
 135     DHCP_OPT(ALL_SUBNETS_ARE_LOCAL,    27, BOOLEAN, 1, 1)               \
 136     DHCP_OPT(BROADCAST_ADDRESS,        28, IP,      1, 1)               \
 137     DHCP_OPT(PERFORM_MASK_DISCOVERY,   29, BOOLEAN, 1, 1)               \
 138     DHCP_OPT(MASK_SUPPLIER,            30, BOOLEAN, 1, 1)               \
 139     DHCP_OPT(PERFORM_ROUTER_DISCOVERY, 31, BOOLEAN, 1, 1)               \
 140     DHCP_OPT(ROUTER_SOLICITATION,      32, IP,      1, 1)               \
 141     DHCP_OPT(STATIC_ROUTE,             33, IP,      2, SIZE_MAX)        \
 142     /* Trailer Encapsulation Option is obsolete. */                     \
 143     DHCP_OPT(ARP_CACHE_TIMEOUT,        35, SECS,    1, 1)               \
 144     DHCP_OPT(ETHERNET_ENCAPSULATION,   36, BOOLEAN, 1, 1)               \
 145     DHCP_OPT(TCP_TTL,                  37, UINT8,   1, 1)               \
 146     DHCP_OPT(TCP_KEEPALIVE_INTERVAL,   38, SECS,    1, 1)               \
 147     DHCP_OPT(TCP_KEEPALIVE_GARBAGE,    39, BOOLEAN, 1, 1)               \
 148     DHCP_OPT(NIS_DOMAIN,               40, STRING,  1, SIZE_MAX)        \
 149     DHCP_OPT(NIS_SERVERS,              41, IP,      1, SIZE_MAX)        \
 150     DHCP_OPT(NTP_SERVERS,              42, IP,      1, SIZE_MAX)        \
 151     DHCP_OPT(VENDOR_SPECIFIC,          43, UINT8,   1, SIZE_MAX)        \
 152     DHCP_OPT(NETBIOS_NS,               44, IP,      1, SIZE_MAX)        \
 153     DHCP_OPT(NETBIOS_DDS,              45, IP,      1, SIZE_MAX)        \
 154     DHCP_OPT(NETBIOS_NODE_TYPE,        46, UINT8,   1, 1)               \
 155     DHCP_OPT(NETBIOS_SCOPE,            47, STRING,  1, SIZE_MAX)        \
 156     DHCP_OPT(X_FONT_SERVER,            48, IP,      1, SIZE_MAX)        \
 157     DHCP_OPT(XDM,                      49, IP,      1, SIZE_MAX)        \
 158     DHCP_OPT(NISPLUS_DOMAIN,           64, STRING,  1, SIZE_MAX)        \
 159     DHCP_OPT(NISPLUS_SERVERS,          65, IP,      1, SIZE_MAX)        \
 160     DHCP_OPT(MOBILE_IP_HOME_AGENT,     68, IP,      0, SIZE_MAX)        \
 161     DHCP_OPT(SMTP_SERVER,              69, IP,      1, SIZE_MAX)        \
 162     DHCP_OPT(POP3_SERVER,              70, IP,      1, SIZE_MAX)        \
 163     DHCP_OPT(NNTP_SERVER,              71, IP,      1, SIZE_MAX)        \
 164     DHCP_OPT(WWW_SERVER,               72, IP,      1, SIZE_MAX)        \
 165     DHCP_OPT(FINGER_SERVER,            73, IP,      1, SIZE_MAX)        \
 166     DHCP_OPT(IRC_SERVER,               74, IP,      1, SIZE_MAX)        \
 167     /* StreetTalk Server Option is obsolete. */                         \
 168     /* StreetTalk Directory Assistance Server Option is obsolete. */    \
 169     DHCP_OPT(REQUESTED_IP,             50, IP,      1, 1)               \
 170     DHCP_OPT(LEASE_TIME,               51, SECS,    1, 1)               \
 171     DHCP_OPT(OPTION_OVERLOAD,          52, UINT8,   1, 1)               \
 172     DHCP_OPT(TFTP_SERVER,              66, STRING,  1, SIZE_MAX)        \
 173     DHCP_OPT(BOOTFILE_NAME,            67, STRING,  1, SIZE_MAX)        \
 174     DHCP_OPT(DHCP_MSG_TYPE,            53, UINT8,   1, 1)               \
 175     DHCP_OPT(SERVER_IDENTIFIER,        54, IP,      1, 1)               \
 176     DHCP_OPT(PARAMETER_REQUEST_LIST,   55, UINT8,   1, SIZE_MAX)        \
 177     DHCP_OPT(MESSAGE,                  56, STRING,  1, SIZE_MAX)        \
 178     DHCP_OPT(MAX_DHCP_MSG_SIZE,        57, UINT16,  1, 1)               \
 179     DHCP_OPT(T1,                       58, SECS,    1, 1)               \
 180     DHCP_OPT(T2,                       59, SECS,    1, 1)               \
 181     DHCP_OPT(VENDOR_CLASS,             60, STRING,  1, SIZE_MAX)        \
 182     DHCP_OPT(CLIENT_ID,                61, UINT8,   2, SIZE_MAX)        \
 183     DHCP_VNDOPT(OFP_CONTROLLER_VCONN,   1, STRING,  1, SIZE_MAX)        \
 184     DHCP_VNDOPT(OFP_PKI_URI,            2, STRING,  1, SIZE_MAX)
 185
 186 /* Shorthand for defining vendor options (used above). */
 187 #define DHCP_VNDOPT(NAME, CODE, ARG, MIN, MAX) \
 188     DHCP_OPT(NAME, (CODE) + DHCP_VENDOR_OFS, ARG, MIN, MAX)
 189
 190 /* DHCP option codes. */
 191 enum {
 192 #define DHCP_OPT(NAME, VALUE, ARGTYPE, MIN_ARGS, MAX_ARGS) \
 193     DHCP_CODE_##NAME = VALUE,
 194 DHCP_OPTS
 195 #undef DHCP_OPT
 196 };
 197
 198 /* The contents of a DHCP option.
 199  *
 200  * DHCP options can (rarely) be present but lack content.  To represent such an
 201  * option, 'n' is 0 and 'data' is non-null (but does not point to anything
 202  * useful).  */
 203 struct dhcp_option {
 204     size_t n;                   /* Number of bytes of data. */
 205     void *data;                 /* Data. */
 206 };
 207
 208 const char *dhcp_option_to_string(const struct dhcp_option *, int code,
 209                                   struct ds *);
 210 bool dhcp_option_equals(const struct dhcp_option *,
 211                         const struct dhcp_option *);
 212
 213 /* Abstracted DHCP protocol message, to make them easier to manipulate than
 214  * through raw protocol buffers. */
 215 struct dhcp_msg {
 216     /* For use by calling code. */
 217     uint8_t op;                 /* DHCP_BOOTREQUEST or DHCP_BOOTREPLY. */
 218     uint32_t xid;               /* Transaction ID. */
 219     uint16_t secs;              /* Since client started address acquisition. */
 220     uint16_t flags;             /* DHCP_FLAGS_*. */
 221     uint32_t ciaddr;            /* Client IP, if it has a lease for one. */
 222     uint32_t yiaddr;            /* Client ("your") IP address. */
 223     uint32_t siaddr;            /* Next server IP address. */
 224     uint32_t giaddr;            /* Relay agent IP address. */
 225     uint8_t chaddr[ETH_ADDR_LEN]; /* Client hardware address. */
 226     enum dhcp_msg_type type;    /* DHCP_CODE_DHCP_MSG_TYPE option argument. */
 227     struct dhcp_option options[DHCP_N_OPTIONS]; /* Indexed by option code. */
 228
 229     /* For direct use only by dhcp_msg_*() functions. */
 230     uint8_t *data;
 231     size_t data_used, data_allocated;
 232 };
 233
 234 void dhcp_msg_init(struct dhcp_msg *);
 235 void dhcp_msg_uninit(struct dhcp_msg *);
 236 void dhcp_msg_copy(struct dhcp_msg *, const struct dhcp_msg *);
 237 void dhcp_msg_put(struct dhcp_msg *, int code, const void *, size_t);
 238 void dhcp_msg_put_bool(struct dhcp_msg *, int code, bool);
 239 void dhcp_msg_put_secs(struct dhcp_msg *, int code, uint32_t);
 240 void dhcp_msg_put_ip(struct dhcp_msg *, int code, uint32_t);
 241 void dhcp_msg_put_string(struct dhcp_msg *, int code, const char *);
 242 void dhcp_msg_put_uint8(struct dhcp_msg *, int code, uint8_t);
 243 void dhcp_msg_put_uint8_array(struct dhcp_msg *, int code,
 244                               const uint8_t[], size_t n);
 245 void dhcp_msg_put_uint16(struct dhcp_msg *, int code, uint16_t);
 246 void dhcp_msg_put_uint16_array(struct dhcp_msg *, int code,
 247                                const uint16_t[], size_t n);
 248 const void *dhcp_msg_get(const struct dhcp_msg *, int code, size_t offset,
 249                          size_t size);
 250 bool dhcp_msg_get_bool(const struct dhcp_msg *, int code,
 251                        size_t offset, bool *);
 252 bool dhcp_msg_get_secs(const struct dhcp_msg *, int code,
 253                        size_t offset, uint32_t *);
 254 bool dhcp_msg_get_ip(const struct dhcp_msg *, int code,
 255                      size_t offset, uint32_t *);
 256 char *dhcp_msg_get_string(const struct dhcp_msg *, int code);
 257 bool dhcp_msg_get_uint8(const struct dhcp_msg *, int code,
 258                         size_t offset, uint8_t *);
 259 bool dhcp_msg_get_uint16(const struct dhcp_msg *, int code,
 260                          size_t offset, uint16_t *);
 261 const char *dhcp_msg_to_string(const struct dhcp_msg *, bool multiline,
 262                                struct ds *);
 263 int dhcp_parse(struct dhcp_msg *, const struct ofpbuf *);
 264 void dhcp_assemble(const struct dhcp_msg *, struct ofpbuf *);
 265
 266 #endif /* dhcp.h */