cmd-inet/usr.sbin/ipaddrsel.c

	ipaddrsel.c revision 0c6f1683238ba0627fb13bb20513e4917993c79d
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include <libintl.h>
#include <locale.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/param.h>
#include <sys/types.h>
#include <stropts.h>
#include <sys/conf.h>
#include <sys/socket.h>
#include <sys/sockio.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <inet/ip.h>
#include <inet/ip6_asp.h>

/*
 * The size of the table we initially use to retrieve the kernel's policy
 * table.  If this value is too small, we use the value returned from the
 * SIOCGIP6ADDRPOLICY ioctl.
 */
#define KERN_POLICY_SIZE    32
#define IPV6DAS_MAXLINELEN  1024
#define IPV6DAS_MAXENTRIES  512

typedef enum {
    IPV6DAS_PRINTPOLICY,
    IPV6DAS_SETPOLICY,
    IPV6DAS_SETDEFAULT
} ipv6das_cmd_t;

static char *myname;    /* Copied from argv[0] */

static int  parseconf(const char *, ip6_asp_t **);
static int  setpolicy(int, ip6_asp_t *, int);
static int  printpolicy(int);
static int  ip_mask_to_plen_v6(const in6_addr_t *);
static in6_addr_t *ip_plen_to_mask_v6(int, in6_addr_t *);
static int  strioctl(int, int, void *, int);
static void usage(void);

int
main(int argc, char **argv)
{
    int     opt, status, sock, count;
    char        *conf_filename;
    ipv6das_cmd_t   ipv6das_cmd = IPV6DAS_PRINTPOLICY;
    ip6_asp_t   *policy_table;

    myname = *argv;

    (void) setlocale(LC_ALL, "");

#if !defined(TEXT_DOMAIN)   /* Should be defined by cc -D */
#define TEXT_DOMAIN "SYS_TEST"
#endif

    (void) textdomain(TEXT_DOMAIN);

    while ((opt = getopt(argc, argv, "df:")) != EOF)
        switch (opt) {
        case 'd':
            ipv6das_cmd = IPV6DAS_SETDEFAULT;
            break;
        case 'f':
            conf_filename = optarg;
            ipv6das_cmd = IPV6DAS_SETPOLICY;
            break;
        default:
            usage();
            return (EXIT_FAILURE);
        }
    if (argc > optind) {
        /* shouldn't be any extra args */
        usage();
        return (EXIT_FAILURE);
    }

    /* Open a socket that we can use to send ioctls down to IP. */
    if ((sock = socket(PF_INET6, SOCK_DGRAM, 0)) == -1) {
        perror("socket");
        return (EXIT_FAILURE);
    }

    switch (ipv6das_cmd) {
    case IPV6DAS_SETPOLICY:
        if ((count = parseconf(conf_filename, &policy_table)) <= 0)
            return (EXIT_FAILURE);
        status = setpolicy(sock, policy_table, count);
        free(policy_table);
        break;
    case IPV6DAS_SETDEFAULT:
        status = setpolicy(sock, NULL, 0);
        break;
    case IPV6DAS_PRINTPOLICY:
    default:
        status = printpolicy(sock);
        break;
    }

    (void) close(sock);
    return (status);
}

/*
 * parseconf(filename, new_policy)
 *
 * Parses the file identified by filename, filling in new_policy
 * with the address selection policy table specified in filename.
 * Returns -1 on failure, or the number of table entries found
 * on success.
 */
static int
parseconf(const char *filename, ip6_asp_t **new_policy)
{
    FILE        *fp;
    char        line[IPV6DAS_MAXLINELEN];
    char        *cp, *end;
    char        *prefixstr;
    uint_t      lineno = 0, entryindex = 0;
    int     plen, precedence;
    char        *label;
    size_t      labellen;
    int     retval;
    ip6_asp_t   tmp_policy[IPV6DAS_MAXENTRIES];
    boolean_t   have_default = B_FALSE;
    in6_addr_t  prefix, mask;
    boolean_t   comment_found = B_FALSE, end_of_line = B_FALSE;

    if ((fp = fopen(filename, "r")) == NULL) {
        perror(filename);
        return (-1);
    }

    while (fgets(line, sizeof (line), fp) != NULL) {
        if (entryindex == IPV6DAS_MAXENTRIES) {
            (void) fprintf(stderr,
                gettext("%s: too many entries\n"), filename);
            retval = -1;
            goto end_parse;
        }

        lineno++;
        cp = line;

        /* Skip leading whitespace */
        while (isspace(*cp))
            cp++;

        /* Is this a comment or blank line? */
        if (*cp == '#' || *cp == '\0')
            continue;

        /*
         * Anything else must be of the form:
         * <IPv6-addr>/<plen> <precedence> <label>
         */
        prefixstr = cp;
        if ((cp = strchr(cp, '/')) == NULL) {
            (void) fprintf(stderr,
                gettext("%s: invalid prefix on line %d: %s\n"),
                filename, lineno, prefixstr);
            continue;
        }
        *cp = '\0';
        if (inet_pton(AF_INET6, prefixstr, &prefix) != 1) {
            (void) fprintf(stderr,
                gettext("%s: invalid prefix on line %d: %s\n"),
                filename, lineno, prefixstr);
            continue;
        }
        cp++;

        errno = 0;
        plen = strtol(cp, &end, 10);
        if (cp == end || errno != 0) {
            (void) fprintf(stderr,
                gettext("%s: invalid prefix length on line %d\n"),
                filename, lineno);
            continue;
        }
        if (ip_plen_to_mask_v6(plen, &mask) == NULL) {
            (void) fprintf(stderr,
                gettext("%s: invalid prefix length on line %d:"
                " %d\n"), filename, lineno, plen);
            continue;
        }
        cp = end;

        errno = 0;
        precedence = strtol(cp, &end, 10);
        if (cp == end || precedence < 0 || errno != 0) {
            (void) fprintf(stderr,
                gettext("%s: invalid precedence on line %d\n"),
                filename, lineno);
            continue;
        }
        cp = end;

        while (isspace(*cp))
            cp++;
        label = cp;
        /*
         * NULL terminate the label string.  The label string is
         * composed of non-blank characters, and can optionally be
         * followed by a comment.
         */
        while (*cp != '\0' && !isspace(*cp) && *cp != '#')
            cp++;
        if (*cp == '#')
            comment_found = B_TRUE;
        else if (*cp == '\0' || *cp == '\n')
            end_of_line = B_TRUE;
        *cp = '\0';

        labellen = cp - label;
        if (labellen == 0) {
            (void) fprintf(stderr,
                gettext("%s: missing label on line %d\n"),
                filename, lineno);
            continue;
        }
        if (labellen >= IP6_ASP_MAXLABELSIZE) {
            (void) fprintf(stderr,
                gettext("%s: label too long on line %d, labels "
                "have a %d character limit.\n"), filename, lineno,
                IP6_ASP_MAXLABELSIZE - 1);
            continue;
        }

        tmp_policy[entryindex].ip6_asp_prefix = prefix;
        tmp_policy[entryindex].ip6_asp_mask = mask;
        tmp_policy[entryindex].ip6_asp_precedence = precedence;
        /*
         * We're specifically using strncpy() to copy the label
         * to take advantage of the fact that strncpy will add
         * NULL characters to the target string up to the given
         * length, so don't change the call to strncpy() with
         * out also taking into account this requirement.  The
         * labels are stored in the kernel in that way in order
         * to make comparisons more efficient: all 16 bytes of
         * the labels are compared to each other; random bytes
         * after the NULL terminator would yield incorrect
         * comparisons.
         */
        (void) strncpy(tmp_policy[entryindex].ip6_asp_label, label,
            IP6_ASP_MAXLABELSIZE);

        /*
         * Anything else on the line should be a comment; print
         * a warning if that's not the case.
         */
        if (!comment_found && !end_of_line) {
            cp++;
            while (*cp != '\0' && isspace(*cp) && *cp != '#')
                cp++;
            if (*cp != '\0' && *cp != '#') {
                (void) fprintf(stderr,
                    gettext("%s: characters following label "
                    "on line %d will be ignored\n"),
                    filename, lineno);
            }
        }

        if (IN6_IS_ADDR_UNSPECIFIED(&prefix) && plen == 0)
            have_default = B_TRUE;

        comment_found = B_FALSE;
        end_of_line = B_FALSE;
        entryindex++;
    }

    if (!have_default) {
        (void) fprintf(stderr,
            gettext("%s: config doesn't contain a default entry.\n"),
            filename);
        retval = -1;
        goto end_parse;
    }

    /* Allocate the caller's array. */
    if ((*new_policy = malloc(entryindex * sizeof (ip6_asp_t))) == NULL) {
        perror("malloc");
        retval = -1;
        goto end_parse;
    }

    (void) memcpy(*new_policy, tmp_policy, entryindex * sizeof (ip6_asp_t));
    retval = entryindex;

end_parse:
    (void) fclose(fp);
    return (retval);
}

/*
 * setpolicy(sock, new_policy, count)
 *
 * Sends an SIOCSIP6ADDRPOLICY ioctl to the kernel to set the address
 * selection policy table pointed to by new_policy.  count should be
 * the number of entries in the table; sock should be an open INET6
 * socket.  Returns EXIT_FAILURE or EXIT_SUCCESS.
 */
static int
setpolicy(int sock, ip6_asp_t *new_policy, int count)
{
    if (strioctl(sock, SIOCSIP6ADDRPOLICY, new_policy,
        count * sizeof (ip6_asp_t)) < 0) {
        perror("SIOCSIP6ADDRPOLICY");
        return (EXIT_FAILURE);
    }
    return (EXIT_SUCCESS);
}

/*
 * printpolicy(sock)
 *
 * Queries the kernel for the current address selection policy using
 * the open socket sock, and prints the result.  Returns EXIT_FAILURE
 * if the table cannot be obtained, or EXIT_SUCCESS if the table is
 * obtained and printed successfully.
 */
static int
printpolicy(int sock)
{
    ip6_asp_t   policy[KERN_POLICY_SIZE];
    ip6_asp_t   *policy_ptr = policy;
    int     count, policy_index;
    char        prefixstr[INET6_ADDRSTRLEN + sizeof ("/128")];

    if ((count = strioctl(sock, SIOCGIP6ADDRPOLICY, policy_ptr,
        KERN_POLICY_SIZE * sizeof (ip6_asp_t))) < 0) {
        perror("SIOCGIP6ADDRPOLICY");
        return (EXIT_FAILURE);
    }
    if (count > KERN_POLICY_SIZE) {
        policy_ptr = malloc(count * sizeof (ip6_asp_t));
        if (policy_ptr == NULL) {
            perror("malloc");
            return (EXIT_FAILURE);
        }
        if ((count = strioctl(sock, SIOCGIP6ADDRPOLICY, policy_ptr,
            count * sizeof (ip6_asp_t))) < 0) {
            perror("SIOCGIP6ADDRPOLICY");
            return (EXIT_FAILURE);
        }
    }

    if (count == 0) {
        /*
         * There should always at least be a default entry in the
         * policy table, so the minimum acceptable value of
         * policy_count is 1.
         */
        (void) fprintf(stderr, gettext("%s: ERROR: "
            "IPv6 address selection policy is empty.\n"), myname);
        return (EXIT_FAILURE);
    }

    /*
     * The format printed here must also be parsable by parseconf(),
     * since we expect users to be able to redirect this output to
     * a usable configuration file if need be.
     */
    (void) printf("# Prefix                  "
        "                    Precedence Label\n");
    for (policy_index = 0; policy_index < count; policy_index++) {
        (void) snprintf(prefixstr, sizeof (prefixstr), "%s/%d",
            inet_ntop(AF_INET6,
            &policy_ptr[policy_index].ip6_asp_prefix, prefixstr,
            sizeof (prefixstr)),
            ip_mask_to_plen_v6(&policy_ptr[policy_index].ip6_asp_mask));
        (void) printf("%-45s %10d %s\n", prefixstr,
            policy_ptr[policy_index].ip6_asp_precedence,
            policy_ptr[policy_index].ip6_asp_label);
    }

    if (policy_ptr != policy)
        free(policy_ptr);
    return (EXIT_SUCCESS);
}

/*
 * ip_mask_to_plen_v6(v6mask)
 *
 * This function takes a mask and returns number of bits set in the
 * mask (the represented prefix length).  Assumes a contigious mask.
 */
int
ip_mask_to_plen_v6(const in6_addr_t *v6mask)
{
    uint8_t     bits;
    uint32_t    mask;
    int     i;

    if (v6mask->_S6_un._S6_u32[3] == 0xffffffff) /* check for all ones */
        return (IPV6_ABITS);

    /* Find number of words with 32 ones */
    bits = 0;
    for (i = 0; i < 4; i++) {
        if (v6mask->_S6_un._S6_u32[i] == 0xffffffff) {
            bits += 32;
            continue;
        }
        break;
    }

    /*
     * Find number of bits in the last word by searching
     * for the first one from the right
     */
    mask = ntohl(v6mask->_S6_un._S6_u32[i]);
    if (mask == 0)
        return (bits);

    return (bits + 32 - (ffs(mask) - 1));
}

/*
 * ip_plen_to_mask_v6(plen, bitmask)
 *
 * Convert a prefix length to the mask for that prefix.
 * Returns the argument bitmask.
 */
in6_addr_t *
ip_plen_to_mask_v6(int plen, in6_addr_t *bitmask)
{
    uint32_t *ptr;

    if (plen > IPV6_ABITS || plen < 0)
        return (NULL);

    (void) memset(bitmask, 0, sizeof (in6_addr_t));
    if (plen == 0)
        return (bitmask);

    ptr = (uint32_t *)bitmask;
    while (plen > 32) {
        *ptr++ = 0xffffffffU;
        plen -= 32;
    }
    *ptr = htonl(0xffffffffU << (32 - plen));
    return (bitmask);
}

/*
 * strioctl(fd, cmd, ptr, ilen)
 *
 * Passes an I_STR ioctl to fd.  The ioctl type is specified by cmd, and
 * any date to be sent down is specified by a pointer to the buffer (ptr)
 * and the buffer size (ilen).  Returns the return value from the ioctl()
 * call.
 */
static int
strioctl(int fd, int cmd, void *ptr, int ilen)
{
    struct strioctl str;
    int retv;

    str.ic_cmd = cmd;
    str.ic_timout = 0;
    str.ic_len = ilen;
    str.ic_dp = ptr;

    while ((retv = ioctl(fd, I_STR, &str)) == -1) {
        if (errno != EINTR)
            break;
    }
    return (retv);
}

static void
usage(void)
{
    (void) fprintf(stderr, gettext(
        "Usage: %s\n"
        "       %s -f <filename>\n"
        "       %s -d\n"), myname, myname, myname);
}