lib/addr.c

/*
 * lib/addr.c           Abstract Address
 *
 *      This library is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU Lesser General Public
 *      License as published by the Free Software Foundation version 2.1
 *      of the License.
 *
 * Copyright (c) 2003-2006 Thomas Graf <tgraf@suug.ch>
 */

/**
 * @ingroup utils
 * @defgroup addr Abstract Address
 *
 * @par 1) Transform character string to abstract address
 * @code
 * struct nl_addr *a = nl_addr_parse("::1", AF_UNSPEC);
 * printf("Address family: %s\n", nl_af2str(nl_addr_get_family(a)));
 * nl_addr_put(a);
 * a = nl_addr_parse("11:22:33:44:55:66", AF_UNSPEC);
 * printf("Address family: %s\n", nl_af2str(nl_addr_get_family(a)));
 * nl_addr_put(a);
 * @endcode
 * @{
 */

#include <netlink-local.h>
#include <netlink/netlink.h>
#include <netlink/utils.h>
#include <netlink/addr.h>
#include <linux/socket.h>

/* All this DECnet stuff is stolen from iproute2, thanks to whoever wrote
 * this, probably Alexey. */
static inline uint16_t dn_ntohs(uint16_t addr)
{
        union {
                uint8_t byte[2];
                uint16_t word;
        } u = {
                .word = addr,
        };

        return ((uint16_t) u.byte[0]) | (((uint16_t) u.byte[1]) << 8);
}

static inline int do_digit(char *str, uint16_t *addr, uint16_t scale,
                           size_t *pos, size_t len, int *started)
{
        uint16_t tmp = *addr / scale;

        if (*pos == len)
                return 1;

        if (((tmp) > 0) || *started || (scale == 1)) {
                *str = tmp + '0';
                *started = 1;
                (*pos)++;
                *addr -= (tmp * scale);
        }

        return 0;
}

static const char *dnet_ntop(char *addrbuf, size_t addrlen, char *str,
                             size_t len)
{
        uint16_t addr = dn_ntohs(*(uint16_t *)addrbuf);
        uint16_t area = addr >> 10;
        size_t pos = 0;
        int started = 0;

        if (addrlen != 2)
                return NULL;

        addr &= 0x03ff;

        if (len == 0)
                return str;

        if (do_digit(str + pos, &area, 10, &pos, len, &started))
                return str;

        if (do_digit(str + pos, &area, 1, &pos, len, &started))
                return str;

        if (pos == len)
                return str;

        *(str + pos) = '.';
        pos++;
        started = 0;

        if (do_digit(str + pos, &addr, 1000, &pos, len, &started))
                return str;

        if (do_digit(str + pos, &addr, 100, &pos, len, &started))
                return str;

        if (do_digit(str + pos, &addr, 10, &pos, len, &started))
                return str;

        if (do_digit(str + pos, &addr, 1, &pos, len, &started))
                return str;

        if (pos == len)
                return str;

        *(str + pos) = 0;

        return str;
}

static int dnet_num(const char *src, uint16_t * dst)
{
        int rv = 0;
        int tmp;
        *dst = 0;

        while ((tmp = *src++) != 0) {
                tmp -= '0';
                if ((tmp < 0) || (tmp > 9))
                        return rv;

                rv++;
                (*dst) *= 10;
                (*dst) += tmp;
        }

        return rv;
}

static inline int dnet_pton(const char *src, char *addrbuf)
{
        uint16_t area = 0;
        uint16_t node = 0;
        int pos;

        pos = dnet_num(src, &area);
        if ((pos == 0) || (area > 63) ||
            ((*(src + pos) != '.') && (*(src + pos) != ',')))
                return -EINVAL;

        pos = dnet_num(src + pos + 1, &node);
        if ((pos == 0) || (node > 1023))
                return -EINVAL;

        *(uint16_t *)addrbuf = dn_ntohs((area << 10) | node);

        return 1;
}

/**
 * @name Creating Abstract Addresses
 * @{
 */

/**
 * Allocate new abstract address object.
 * @arg maxsize         Maximum size of the binary address.
 * @return Newly allocated address object or NULL
 */
struct nl_addr *nl_addr_alloc(size_t maxsize)
{
        struct nl_addr *addr;
        
        addr = calloc(1, sizeof(*addr) + maxsize);
        if (!addr) {
                nl_errno(ENOMEM);
                return NULL;
        }

        addr->a_refcnt = 1;
        addr->a_maxsize = maxsize;

        return addr;
}

/**
 * Allocate new abstract address object based on a binary address.
 * @arg family          Address family.
 * @arg buf             Buffer containing the binary address.
 * @arg size            Length of binary address buffer.
 * @return Newly allocated address handle or NULL
 */
struct nl_addr *nl_addr_build(int family, void *buf, size_t size)
{
        struct nl_addr *addr;

        addr = nl_addr_alloc(size);
        if (!addr)
                return NULL;

        addr->a_family = family;
        addr->a_len = size;
        addr->a_prefixlen = size*8;

        if (size)
                memcpy(addr->a_addr, buf, size);

        return addr;
}

/**
 * Allocate abstract address object based on a character string
 * @arg addrstr         Address represented as character string.
 * @arg hint            Address family hint or AF_UNSPEC.
 *
 * Regognizes the following address formats:
 *@code
 *  Format                      Len                Family
 *  ----------------------------------------------------------------
 *  IPv6 address format         16                 AF_INET6
 *  ddd.ddd.ddd.ddd             4                  AF_INET
 *  HH:HH:HH:HH:HH:HH           6                  AF_LLC
 *  AA{.|,}NNNN                 2                  AF_DECnet
 *  HH:HH:HH:...                variable           AF_UNSPEC
 * @endcode
 *
 *  Special values:
 *    - none: All bits and length set to 0.
 *    - {default|all|any}: All bits set to 0, length based on hint or
 *                         AF_INET if no hint is given.
 *
 * The prefix length may be appened at the end prefixed with a
 * slash, e.g. 10.0.0.0/8.
 *
 * @return Newly allocated abstract address object or NULL.
 */
struct nl_addr *nl_addr_parse(const char *addrstr, int hint)
{
        int err, copy = 0, len = 0, family = AF_UNSPEC;
        char *str, *prefix, buf[32];
        struct nl_addr *addr = NULL; /* gcc ain't that smart */

        str = strdup(addrstr);
        if (!str) {
                err = nl_errno(ENOMEM);
                goto errout;
        }

        prefix = strchr(str, '/');
        if (prefix)
                *prefix = '\0';

        if (!strcasecmp(str, "none")) {
                family = hint;
                goto prefix;
        }

        if (!strcasecmp(str, "default") ||
            !strcasecmp(str, "all") ||
            !strcasecmp(str, "any")) {
                        
                switch (hint) {
                        case AF_INET:
                        case AF_UNSPEC:
                                /* Kind of a hack, we assume that if there is
                                 * no hint given the user wants to have a IPv4
                                 * address given back. */
                                family = AF_INET;
                                len = 4;
                                goto prefix;

                        case AF_INET6:
                                family = AF_INET6;
                                len = 16;
                                goto prefix;

                        case AF_LLC:
                                family = AF_LLC;
                                len = 6;
                                goto prefix;

                        default:
                                err = nl_error(EINVAL, "Unsuported address" \
                                    "family for default address");
                                goto errout;
                }
        }

        copy = 1;

        if (hint == AF_INET || hint == AF_UNSPEC) {
                if (inet_pton(AF_INET, str, buf) > 0) {
                        family = AF_INET;
                        len = 4;
                        goto prefix;
                }
                if (hint == AF_INET) {
                        err = nl_error(EINVAL, "Invalid IPv4 address");
                        goto errout;
                }
        }

        if (hint == AF_INET6 || hint == AF_UNSPEC) {
                if (inet_pton(AF_INET6, str, buf) > 0) {
                        family = AF_INET6;
                        len = 16;
                        goto prefix;
                }
                if (hint == AF_INET6) {
                        err = nl_error(EINVAL, "Invalid IPv6 address");
                        goto errout;
                }
        }

        if ((hint == AF_LLC || hint == AF_UNSPEC) && strchr(str, ':')) {
                unsigned int a, b, c, d, e, f;

                if (sscanf(str, "%02x:%02x:%02x:%02x:%02x:%02x",
                    &a, &b, &c, &d, &e, &f) == 6) {
                        family = AF_LLC;
                        len = 6;
                        buf[0] = (unsigned char) a;
                        buf[1] = (unsigned char) b;
                        buf[2] = (unsigned char) c;
                        buf[3] = (unsigned char) d;
                        buf[4] = (unsigned char) e;
                        buf[5] = (unsigned char) f;
                        goto prefix;
                }

                if (hint == AF_LLC) {
                        err = nl_error(EINVAL, "Invalid link layer address");
                        goto errout;
                }
        }

        if ((hint == AF_DECnet || hint == AF_UNSPEC) &&
            (strchr(str, '.') || strchr(str, ','))) {
                if (dnet_pton(str, buf) > 0) {
                        family = AF_DECnet;
                        len = 2;
                        goto prefix;
                }
                if (hint == AF_DECnet) {
                        err = nl_error(EINVAL, "Invalid DECnet address");
                        goto errout;
                }
        }

        if (hint == AF_UNSPEC && strchr(str, ':')) {
                int i = 0;
                char *s = str, *p;
                for (;;) {
                        long l = strtol(s, &p, 16);

                        if (s == p || l > 0xff || i >= sizeof(buf)) {
                                err = -EINVAL;
                                goto errout;
                        }

                        buf[i++] = (unsigned char) l;
                        if (*p == '\0')
                                break;
                        s = ++p;
                }

                len = i;
                family = AF_UNSPEC;
                goto prefix;
        }

        err = nl_error(EINVAL, "Invalid address");
        goto errout;

prefix:
        addr = nl_addr_alloc(len);
        if (!addr) {
                err = nl_errno(ENOMEM);
                goto errout;
        }

        nl_addr_set_family(addr, family);

        if (copy)
                nl_addr_set_binary_addr(addr, buf, len);

        if (prefix) {
                char *p;
                long pl = strtol(++prefix, &p, 0);
                if (p == prefix) {
                        nl_addr_destroy(addr);
                        err = -EINVAL;
                        goto errout;
                }
                nl_addr_set_prefixlen(addr, pl);
        } else
                nl_addr_set_prefixlen(addr, len * 8);

        err = 0;
errout:
        free(str);

        return err ? NULL : addr;
}

/**
 * Clone existing abstract address object.
 * @arg addr            Abstract address object.
 * @return Newly allocated abstract address object being a duplicate of the
 *         specified address object or NULL if a failure occured.
 */
struct nl_addr *nl_addr_clone(struct nl_addr *addr)
{
        struct nl_addr *new;

        new = nl_addr_build(addr->a_family, addr->a_addr, addr->a_len);
        if (new)
                new->a_prefixlen = addr->a_prefixlen;

        return new;
}

/** @} */

/**
 * @name Destroying Abstract Addresses
 * @{
 */

/**
 * Destroy abstract address object.
 * @arg addr            Abstract address object.
 */
void nl_addr_destroy(struct nl_addr *addr)
{
        if (!addr)
                return;

        if (addr->a_refcnt != 1)
                BUG();

        free(addr);
}

/** @} */

/**
 * @name Managing Usage References
 * @{
 */

struct nl_addr *nl_addr_get(struct nl_addr *addr)
{
        addr->a_refcnt++;

        return addr;
}

void nl_addr_put(struct nl_addr *addr)
{
        if (!addr)
                return;

        if (addr->a_refcnt == 1)
                nl_addr_destroy(addr);
        else
                addr->a_refcnt--;
}

/**
 * Check whether an abstract address object is shared.
 * @arg addr            Abstract address object.
 * @return Non-zero if the abstract address object is shared, otherwise 0.
 */
int nl_addr_shared(struct nl_addr *addr)
{
        return addr->a_refcnt > 1;
}

/** @} */

/**
 * @name Miscellaneous
 * @{
 */

/**
 * Compares two abstract address objects.
 * @arg a               A abstract address object.
 * @arg b               Another abstract address object.
 *
 * @return Integer less than, equal to or greather than zero if \c is found,
 *         respectively to be less than, to, or be greater than \c b.
 */
int nl_addr_cmp(struct nl_addr *a, struct nl_addr *b)
{
        int d = a->a_family - b->a_family;

        if (d == 0) {
                d = a->a_len - b->a_len;

                if (a->a_len && d == 0)
                        return memcmp(a->a_addr, b->a_addr, a->a_len);
        }

        return d;
}

/**
 * Compares the prefix of two abstract address objects.
 * @arg a               A abstract address object.
 * @arg b               Another abstract address object.
 *
 * @return Integer less than, equal to or greather than zero if \c is found,
 *         respectively to be less than, to, or be greater than \c b.
 */
int nl_addr_cmp_prefix(struct nl_addr *a, struct nl_addr *b)
{
        int d = a->a_family - b->a_family;

        if (d == 0) {
                int len = min(a->a_prefixlen, b->a_prefixlen);
                int bytes = len / 8;

                d = memcmp(a->a_addr, b->a_addr, bytes);
                if (d == 0) {
                        int mask = (1UL << (len % 8)) - 1UL;

                        d = (a->a_addr[bytes] & mask) -
                            (b->a_addr[bytes] & mask);
                }
        }

        return d;
}

/**
 * Returns true if the address consists of all zeros
 * @arg addr            Address to look at.
 */
int nl_addr_iszero(struct nl_addr *addr)
{
        int i;

        for (i = 0; i < addr->a_len; i++)
                if (addr->a_addr[i])
                        return 0;

        return 1;
}

/**
 * Check if an address matches a certain family.
 * @arg addr            Address represented as character string.
 * @arg family          Desired address family.
 *
 * @return 1 if the address is of the desired address family,
 *         otherwise 0 is returned.
 */
int nl_addr_valid(char *addr, int family)
{
        int ret;
        char buf[32];

        switch (family) {
        case AF_INET:
        case AF_INET6:
                ret = inet_pton(family, addr, buf);
                if (ret <= 0)
                        return 0;
                break;

        case AF_DECnet:
                ret = dnet_pton(addr, buf);
                if (ret <= 0)
                        return 0;
                break;

        case AF_LLC:
                if (sscanf(addr, "%*02x:%*02x:%*02x:%*02x:%*02x:%*02x") != 6)
                        return 0;
                break;
        }

        return 1;
}

/**
 * Guess address family of an abstract address object based on address size.
 * @arg addr            Abstract address object.
 * @return Address family or AF_UNSPEC if guessing wasn't successful.
 */
int nl_addr_guess_family(struct nl_addr *addr)
{
        switch (addr->a_len) {
                case 4:
                        return AF_INET;
                case 6:
                        return AF_LLC;
                case 16:
                        return AF_INET6;
                default:
                        return AF_UNSPEC;
        }
}

/**
 * Fill out sockaddr structure with values from abstract address object.
 * @arg addr            Abstract address object.
 * @arg sa              Destination sockaddr structure buffer.
 * @arg salen           Length of sockaddr structure buffer.
 *
 * Fills out the specified sockaddr structure with the data found in the
 * specified abstract address. The salen argument needs to be set to the
 * size of sa but will be modified to the actual size used during before
 * the function exits.
 *
 * @return 0 on success or a negative error code
 */
int nl_addr_fill_sockaddr(struct nl_addr *addr, struct sockaddr *sa,
                          socklen_t *salen)
{
        switch (addr->a_family) {
        case AF_INET: {
                struct sockaddr_in *sai = (struct sockaddr_in *) sa;

                if (*salen < sizeof(*sai))
                        return -EINVAL;

                sai->sin_family = addr->a_family;
                memcpy(&sai->sin_addr, addr->a_addr, 4);
                *salen = sizeof(*sai);
        }
                break;

        case AF_INET6: {
                struct sockaddr_in6 *sa6 = (struct sockaddr_in6 *) sa;

                if (*salen < sizeof(*sa6))
                        return -EINVAL;

                sa6->sin6_family = addr->a_family;
                memcpy(&sa6->sin6_addr, addr->a_addr, 16);
                *salen = sizeof(*sa6);
        }
                break;

        default:
                return -EINVAL;
        }

        return 0;
}


/** @} */

/**
 * @name Getting Information About Addresses
 * @{
 */

/**
 * Call getaddrinfo() for an abstract address object.
 * @arg addr            Abstract address object.
 * 
 * Calls getaddrinfo() for the specified abstract address in AI_NUMERICHOST
 * mode.
 *
 * @note The caller is responsible for freeing the linked list using the
 *       interface provided by getaddrinfo(3).
 *
 * @return A linked list of addrinfo handles or  NULL with an error message
 *         associated.
 */
struct addrinfo *nl_addr_info(struct nl_addr *addr)
{
        int err;
        struct addrinfo *res;
        char buf[INET6_ADDRSTRLEN+5];
        struct addrinfo hint = {
                .ai_flags = AI_NUMERICHOST,
                .ai_family = addr->a_family,
        };

        nl_addr2str(addr, buf, sizeof(buf));

        err = getaddrinfo(buf, NULL, &hint, &res);
        if (err != 0) {
                nl_error(err, gai_strerror(err));
                return NULL;
        }

        return res;
}

/**
 * Resolve abstract address object to a name using getnameinfo().
 * @arg addr            Abstract address object.
 * @arg host            Destination buffer for host name.
 * @arg hostlen         Length of destination buffer.
 *
 * Resolves the abstract address to a name and writes the looked up result
 * into the host buffer. getnameinfo() is used to perform the lookup and
 * is put into NI_NAMEREQD mode so the function will fail if the lookup
 * couldn't be performed.
 *
 * @return 0 on success or a negative error code.
 */
int nl_addr_resolve(struct nl_addr *addr, char *host, size_t hostlen)
{
        int err;
        struct sockaddr_in6 buf;
        socklen_t salen = sizeof(buf);

        err = nl_addr_fill_sockaddr(addr, (struct sockaddr *) &buf, &salen);
        if (err < 0)
                return err;

        return getnameinfo((struct sockaddr *) &buf, salen,
                           host, hostlen, NULL, 0, NI_NAMEREQD);
}

/** @} */

/**
 * @name Attributes
 * @{
 */

void nl_addr_set_family(struct nl_addr *addr, int family)
{
        addr->a_family = family;
}

int nl_addr_get_family(struct nl_addr *addr)
{
        return addr->a_family;
}

/**
 * Set binary address of abstract address object.
 * @arg addr            Abstract address object.
 * @arg buf             Buffer containing binary address.
 * @arg len             Length of buffer containing binary address.
 */
int nl_addr_set_binary_addr(struct nl_addr *addr, void *buf, size_t len)
{
        if (len > addr->a_maxsize)
                return -ERANGE;

        addr->a_len = len;
        memcpy(addr->a_addr, buf, len);

        return 0;
}

/**
 * Get binary address of abstract address object.
 * @arg addr            Abstract address object.
 */
void *nl_addr_get_binary_addr(struct nl_addr *addr)
{
        return addr->a_addr;
}

/**
 * Get length of binary address of abstract address object.
 * @arg addr            Abstract address object.
 */
unsigned int nl_addr_get_len(struct nl_addr *addr)
{
        return addr->a_len;
}

void nl_addr_set_prefixlen(struct nl_addr *addr, int prefixlen)
{
        addr->a_prefixlen = prefixlen;
}

/**
 * Get prefix length of abstract address object.
 * @arg addr            Abstract address object.
 */
unsigned int nl_addr_get_prefixlen(struct nl_addr *addr)
{
        return addr->a_prefixlen;
}

/** @} */

/**
 * @name Translations to Strings
 * @{
 */

/**
 * Convert abstract address object to character string.
 * @arg addr            Abstract address object.
 * @arg buf             Destination buffer.
 * @arg size            Size of destination buffer.
 *
 * Converts an abstract address to a character string and stores
 * the result in the specified destination buffer.
 *
 * @return Address represented in ASCII stored in destination buffer.
 */
char *nl_addr2str(struct nl_addr *addr, char *buf, size_t size)
{
        int i;
        char tmp[16];

        if (!addr->a_len) {
                snprintf(buf, size, "none");
                goto prefix;
        }

        switch (addr->a_family) {
                case AF_INET:
                        inet_ntop(AF_INET, addr->a_addr, buf, size);
                        break;

                case AF_INET6:
                        inet_ntop(AF_INET6, addr->a_addr, buf, size);
                        break;

                case AF_DECnet:
                        dnet_ntop(addr->a_addr, addr->a_len, buf, size);
                        break;

                case AF_LLC:
                default:
                        snprintf(buf, size, "%02x",
                                 (unsigned char) addr->a_addr[0]);
                        for (i = 1; i < addr->a_len; i++) {
                                snprintf(tmp, sizeof(tmp), ":%02x",
                                         (unsigned char) addr->a_addr[i]);
                                strncat(buf, tmp, size - strlen(buf) - 1);
                        }
                        break;
        }

prefix:
        if (addr->a_prefixlen != (8 * addr->a_len)) {
                snprintf(tmp, sizeof(tmp), "/%u", addr->a_prefixlen);
                strncat(buf, tmp, size - strlen(buf) - 1);
        }

        return buf;
}

/** @} */

/**
 * @name Address Family Transformations
 * @{
 */

static struct trans_tbl afs[] = {
        __ADD(AF_UNSPEC,unspec)
        __ADD(AF_UNIX,unix)
        __ADD(AF_LOCAL,local)
        __ADD(AF_INET,inet)
        __ADD(AF_AX25,ax25)
        __ADD(AF_IPX,ipx)
        __ADD(AF_APPLETALK,appletalk)
        __ADD(AF_NETROM,netrom)
        __ADD(AF_BRIDGE,bridge)
        __ADD(AF_ATMPVC,atmpvc)
        __ADD(AF_X25,x25)
        __ADD(AF_INET6,inet6)
        __ADD(AF_ROSE,rose)
        __ADD(AF_DECnet,decnet)
        __ADD(AF_NETBEUI,netbeui)
        __ADD(AF_SECURITY,security)
        __ADD(AF_KEY,key)
        __ADD(AF_NETLINK,netlink)
        __ADD(AF_ROUTE,route)
        __ADD(AF_PACKET,packet)
        __ADD(AF_ASH,ash)
        __ADD(AF_ECONET,econet)
        __ADD(AF_ATMSVC,atmsvc)
        __ADD(AF_SNA,sna)
        __ADD(AF_IRDA,irda)
        __ADD(AF_PPPOX,pppox)
        __ADD(AF_WANPIPE,wanpipe)
        __ADD(AF_LLC,llc)
        __ADD(AF_BLUETOOTH,bluetooth)
};

char *nl_af2str(int family, char *buf, size_t size)
{
        return __type2str(family, buf, size, afs, ARRAY_SIZE(afs));
}

int nl_str2af(const char *name)
{
        int fam = __str2type(name, afs, ARRAY_SIZE(afs));
        return fam >= 0 ? fam : AF_UNSPEC;
}

/** @} */

/** @} */

---