source: MondoRescue/branches/stable/mindi-busybox/networking/udhcp/files.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * files.c -- DHCP server file manipulation *
 * Rewrite by Russ Dill <Russ.Dill@asu.edu> July 2001
 */

#include <netinet/ether.h>

#include "common.h"
#include "dhcpd.h"
#include "options.h"


/* on these functions, make sure your datatype matches */
static int read_ip(const char *line, void *arg)
{
    len_and_sockaddr *lsa;

    lsa = host_and_af2sockaddr(line, 0, AF_INET);
    if (!lsa)
        return 0;
    *(uint32_t*)arg = lsa->sin.sin_addr.s_addr;
    free(lsa);
    return 1;
}

static int read_mac(const char *line, void *arg)
{
    uint8_t *mac_bytes = arg;
    struct ether_addr *temp_ether_addr;

    temp_ether_addr = ether_aton(line);
    if (temp_ether_addr == NULL)
        return 0;
    memcpy(mac_bytes, temp_ether_addr, 6);
    return 1;
}


static int read_str(const char *line, void *arg)
{
    char **dest = arg;

    free(*dest);
    *dest = xstrdup(line);
    return 1;
}


static int read_u32(const char *line, void *arg)
{
    *(uint32_t*)arg = bb_strtou32(line, NULL, 10);
    return errno == 0;
}


static int read_yn(const char *line, void *arg)
{
    char *dest = arg;

    if (!strcasecmp("yes", line)) {
        *dest = 1;
        return 1;
    }
    if (!strcasecmp("no", line)) {
        *dest = 0;
        return 1;
    }
    return 0;
}


/* find option 'code' in opt_list */
struct option_set *find_option(struct option_set *opt_list, char code)
{
    while (opt_list && opt_list->data[OPT_CODE] < code)
        opt_list = opt_list->next;

    if (opt_list && opt_list->data[OPT_CODE] == code)
        return opt_list;
    return NULL;
}


/* add an option to the opt_list */
static void attach_option(struct option_set **opt_list,
        const struct dhcp_option *option, char *buffer, int length)
{
    struct option_set *existing, *new, **curr;

    existing = find_option(*opt_list, option->code);
    if (!existing) {
        DEBUG("Attaching option %s to list", option->name);

#if ENABLE_FEATURE_RFC3397
        if ((option->flags & TYPE_MASK) == OPTION_STR1035)
            /* reuse buffer and length for RFC1035-formatted string */
            buffer = dname_enc(NULL, 0, buffer, &length);
#endif

        /* make a new option */
        new = xmalloc(sizeof(*new));
        new->data = xmalloc(length + 2);
        new->data[OPT_CODE] = option->code;
        new->data[OPT_LEN] = length;
        memcpy(new->data + 2, buffer, length);

        curr = opt_list;
        while (*curr && (*curr)->data[OPT_CODE] < option->code)
            curr = &(*curr)->next;

        new->next = *curr;
        *curr = new;
#if ENABLE_FEATURE_RFC3397
        if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
            free(buffer);
#endif
        return;
    }

    /* add it to an existing option */
    DEBUG("Attaching option %s to existing member of list", option->name);
    if (option->flags & OPTION_LIST) {
#if ENABLE_FEATURE_RFC3397
        if ((option->flags & TYPE_MASK) == OPTION_STR1035)
            /* reuse buffer and length for RFC1035-formatted string */
            buffer = dname_enc(existing->data + 2,
                    existing->data[OPT_LEN], buffer, &length);
#endif
        if (existing->data[OPT_LEN] + length <= 255) {
            existing->data = xrealloc(existing->data,
                    existing->data[OPT_LEN] + length + 3);
            if ((option->flags & TYPE_MASK) == OPTION_STRING) {
                /* ' ' can bring us to 256 - bad */
                if (existing->data[OPT_LEN] + length >= 255)
                    return;
                /* add space separator between STRING options in a list */
                existing->data[existing->data[OPT_LEN] + 2] = ' ';
                existing->data[OPT_LEN]++;
            }
            memcpy(existing->data + existing->data[OPT_LEN] + 2, buffer, length);
            existing->data[OPT_LEN] += length;
        } /* else, ignore the data, we could put this in a second option in the future */
#if ENABLE_FEATURE_RFC3397
        if ((option->flags & TYPE_MASK) == OPTION_STR1035 && buffer != NULL)
            free(buffer);
#endif
    } /* else, ignore the new data */
}


/* read a dhcp option and add it to opt_list */
static int read_opt(const char *const_line, void *arg)
{
    struct option_set **opt_list = arg;
    char *opt, *val, *endptr;
    const struct dhcp_option *option;
    int retval = 0, length;
    char buffer[8];
    char *line;
    uint16_t *result_u16 = (uint16_t *) buffer;
    uint32_t *result_u32 = (uint32_t *) buffer;

    /* Cheat, the only const line we'll actually get is "" */
    line = (char *) const_line;
    opt = strtok(line, " \t=");
    if (!opt) return 0;

    option = dhcp_options;
    while (1) {
        if (!option->code)
            return 0;
        if (!strcasecmp(option->name, opt))
            break;
        option++;
    }

    do {
        val = strtok(NULL, ", \t");
        if (!val) break;
        length = option_lengths[option->flags & TYPE_MASK];
        retval = 0;
        opt = buffer; /* new meaning for variable opt */
        switch (option->flags & TYPE_MASK) {
        case OPTION_IP:
            retval = read_ip(val, buffer);
            break;
        case OPTION_IP_PAIR:
            retval = read_ip(val, buffer);
            val = strtok(NULL, ", \t/-");
            if (!val)
                retval = 0;
            if (retval)
                retval = read_ip(val, buffer + 4);
            break;
        case OPTION_STRING:
#if ENABLE_FEATURE_RFC3397
        case OPTION_STR1035:
#endif
            length = strlen(val);
            if (length > 0) {
                if (length > 254) length = 254;
                opt = val;
                retval = 1;
            }
            break;
        case OPTION_BOOLEAN:
            retval = read_yn(val, buffer);
            break;
        case OPTION_U8:
            buffer[0] = strtoul(val, &endptr, 0);
            retval = (endptr[0] == '\0');
            break;
        /* htonX are macros in older libc's, using temp var
         * in code below for safety */
        /* TODO: use bb_strtoX? */
        case OPTION_U16: {
            unsigned long tmp = strtoul(val, &endptr, 0);
            *result_u16 = htons(tmp);
            retval = (endptr[0] == '\0' /*&& tmp < 0x10000*/);
            break;
        }
        case OPTION_S16: {
            long tmp = strtol(val, &endptr, 0);
            *result_u16 = htons(tmp);
            retval = (endptr[0] == '\0');
            break;
        }
        case OPTION_U32: {
            unsigned long tmp = strtoul(val, &endptr, 0);
            *result_u32 = htonl(tmp);
            retval = (endptr[0] == '\0');
            break;
        }
        case OPTION_S32: {
            long tmp = strtol(val, &endptr, 0);
            *result_u32 = htonl(tmp);
            retval = (endptr[0] == '\0');
            break;
        }
        default:
            break;
        }
        if (retval)
            attach_option(opt_list, option, opt, length);
    } while (retval && option->flags & OPTION_LIST);
    return retval;
}

static int read_staticlease(const char *const_line, void *arg)
{
    char *line;
    char *mac_string;
    char *ip_string;
    uint8_t *mac_bytes;
    uint32_t *ip;

    /* Allocate memory for addresses */
    mac_bytes = xmalloc(sizeof(unsigned char) * 8);
    ip = xmalloc(sizeof(uint32_t));

    /* Read mac */
    line = (char *) const_line;
    mac_string = strtok(line, " \t");
    read_mac(mac_string, mac_bytes);

    /* Read ip */
    ip_string = strtok(NULL, " \t");
    read_ip(ip_string, ip);

    addStaticLease(arg, mac_bytes, ip);

    if (ENABLE_FEATURE_UDHCP_DEBUG) printStaticLeases(arg);

    return 1;
}


struct config_keyword {
    const char *keyword;
    int (*handler)(const char *line, void *var);
    void *var;
    const char *def;
};

static const struct config_keyword keywords[] = {
    /* keyword       handler   variable address               default */
    {"start",        read_ip,  &(server_config.start_ip),     "192.168.0.20"},
    {"end",          read_ip,  &(server_config.end_ip),       "192.168.0.254"},
    {"interface",    read_str, &(server_config.interface),    "eth0"},
    {"option",       read_opt, &(server_config.options),      ""},
    {"opt",          read_opt, &(server_config.options),      ""},
    /* Avoid "max_leases value not sane" warning by setting default
     * to default_end_ip - default_start_ip + 1: */
    {"max_leases",   read_u32, &(server_config.max_leases),   "235"},
    {"remaining",    read_yn,  &(server_config.remaining),    "yes"},
    {"auto_time",    read_u32, &(server_config.auto_time),    "7200"},
    {"decline_time", read_u32, &(server_config.decline_time), "3600"},
    {"conflict_time",read_u32, &(server_config.conflict_time),"3600"},
    {"offer_time",   read_u32, &(server_config.offer_time),   "60"},
    {"min_lease",    read_u32, &(server_config.min_lease),    "60"},
    {"lease_file",   read_str, &(server_config.lease_file),   LEASES_FILE},
    {"pidfile",      read_str, &(server_config.pidfile),      "/var/run/udhcpd.pid"},
    {"notify_file",  read_str, &(server_config.notify_file),  ""},
    {"siaddr",       read_ip,  &(server_config.siaddr),       "0.0.0.0"},
    {"sname",        read_str, &(server_config.sname),        ""},
    {"boot_file",    read_str, &(server_config.boot_file),    ""},
    {"static_lease", read_staticlease, &(server_config.static_leases), ""},
    /* ADDME: static lease */
};


/*
 * Domain names may have 254 chars, and string options can be 254
 * chars long. However, 80 bytes will be enough for most, and won't
 * hog up memory. If you have a special application, change it
 */
#define READ_CONFIG_BUF_SIZE 80

int read_config(const char *file)
{
    FILE *in;
    char buffer[READ_CONFIG_BUF_SIZE], *token, *line;
    int i, lm = 0;

    for (i = 0; i < ARRAY_SIZE(keywords); i++)
        if (keywords[i].def[0])
            keywords[i].handler(keywords[i].def, keywords[i].var);

    in = fopen_or_warn(file, "r");
    if (!in) {
        return 0;
    }

    while (fgets(buffer, READ_CONFIG_BUF_SIZE, in)) {
        char debug_orig[READ_CONFIG_BUF_SIZE];
        char *p;

        lm++;
        p = strchr(buffer, '\n');
        if (p) *p = '\0';
        if (ENABLE_FEATURE_UDHCP_DEBUG) strcpy(debug_orig, buffer);
        p = strchr(buffer, '#');
        if (p) *p = '\0';

        if (!(token = strtok(buffer, " \t"))) continue;
        if (!(line = strtok(NULL, ""))) continue;

        /* eat leading whitespace */
        line = skip_whitespace(line);
        /* eat trailing whitespace */
        i = strlen(line) - 1;
        while (i >= 0 && isspace(line[i]))
            line[i--] = '\0';

        for (i = 0; i < ARRAY_SIZE(keywords); i++)
            if (!strcasecmp(token, keywords[i].keyword))
                if (!keywords[i].handler(line, keywords[i].var)) {
                    bb_error_msg("cannot parse line %d of %s", lm, file);
                    if (ENABLE_FEATURE_UDHCP_DEBUG)
                        bb_error_msg("cannot parse '%s'", debug_orig);
                    /* reset back to the default value */
                    keywords[i].handler(keywords[i].def, keywords[i].var);
                }
    }
    fclose(in);

    server_config.start_ip = ntohl(server_config.start_ip);
    server_config.end_ip = ntohl(server_config.end_ip);

    return 1;
}


void write_leases(void)
{
    int fp;
    unsigned i;
    time_t curr = time(0);
    unsigned long tmp_time;

    fp = open3_or_warn(server_config.lease_file, O_WRONLY|O_CREAT|O_TRUNC, 0666);
    if (fp < 0) {
        return;
    }

    for (i = 0; i < server_config.max_leases; i++) {
        if (leases[i].yiaddr != 0) {

            /* screw with the time in the struct, for easier writing */
            tmp_time = leases[i].expires;

            if (server_config.remaining) {
                if (lease_expired(&(leases[i])))
                    leases[i].expires = 0;
                else leases[i].expires -= curr;
            } /* else stick with the time we got */
            leases[i].expires = htonl(leases[i].expires);
            // FIXME: error check??
            full_write(fp, &leases[i], sizeof(leases[i]));

            /* then restore it when done */
            leases[i].expires = tmp_time;
        }
    }
    close(fp);

    if (server_config.notify_file) {
        char *cmd = xasprintf("%s %s", server_config.notify_file, server_config.lease_file);
        system(cmd);
        free(cmd);
    }
}


void read_leases(const char *file)
{
    int fp;
    unsigned int i = 0;
    struct dhcpOfferedAddr lease;

    fp = open_or_warn(file, O_RDONLY);
    if (fp < 0) {
        return;
    }

    while (i < server_config.max_leases
     && full_read(fp, &lease, sizeof(lease)) == sizeof(lease)
    ) {
        /* ADDME: is it a static lease */
        uint32_t y = ntohl(lease.yiaddr);
        if (y >= server_config.start_ip && y <= server_config.end_ip) {
            lease.expires = ntohl(lease.expires);
            if (!server_config.remaining)
                lease.expires -= time(0);
            if (!(add_lease(lease.chaddr, lease.yiaddr, lease.expires))) {
                bb_error_msg("too many leases while loading %s", file);
                break;
            }
            i++;
        }
    }
    DEBUG("Read %d leases", i);
    close(fp);
}