/* vi: set sw=4 ts=4: */
/*
 * nameif.c - Naming Interfaces based on MAC address for busybox.
 *
 * Written 2000 by Andi Kleen.
 * Busybox port 2002 by Nick Fedchik <nick@fedchik.org.ua>
 *                      Glenn McGrath
 * Extended matching support 2008 by Nico Erfurth <masta@perlgolf.de>
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "libbb.h"
#include <syslog.h>
#include <net/if.h>
#include <netinet/ether.h>
#include <linux/sockios.h>

#ifndef IFNAMSIZ
#define IFNAMSIZ 16
#endif

/* Taken from linux/sockios.h */
#define SIOCSIFNAME     0x8923  /* set interface name */

/* Octets in one Ethernet addr, from <linux/if_ether.h> */
#define ETH_ALEN        6

#ifndef ifr_newname
#define ifr_newname ifr_ifru.ifru_slave
#endif

typedef struct ethtable_s {
        struct ethtable_s *next;
        struct ethtable_s *prev;
        char *ifname;
        struct ether_addr *mac;
#if ENABLE_FEATURE_NAMEIF_EXTENDED
        char *bus_info;
        char *driver;
#endif
} ethtable_t;

#if ENABLE_FEATURE_NAMEIF_EXTENDED
/* Cut'n'paste from ethtool.h */
#define ETHTOOL_BUSINFO_LEN 32
/* these strings are set to whatever the driver author decides... */
struct ethtool_drvinfo {
        uint32_t cmd;
        char  driver[32]; /* driver short name, "tulip", "eepro100" */
        char  version[32];  /* driver version string */
        char  fw_version[32]; /* firmware version string, if applicable */
        char  bus_info[ETHTOOL_BUSINFO_LEN];  /* Bus info for this IF. */
        /* For PCI devices, use pci_dev->slot_name. */
        char  reserved1[32];
        char  reserved2[16];
        uint32_t n_stats;  /* number of u64's from ETHTOOL_GSTATS */
        uint32_t testinfo_len;
        uint32_t eedump_len; /* Size of data from ETHTOOL_GEEPROM (bytes) */
        uint32_t regdump_len;  /* Size of data from ETHTOOL_GREGS (bytes) */
};
#define ETHTOOL_GDRVINFO  0x00000003 /* Get driver info. */
#endif


static void nameif_parse_selector(ethtable_t *ch, char *selector)
{
        struct ether_addr *lmac;
#if ENABLE_FEATURE_NAMEIF_EXTENDED
        int found_selector = 0;

        while (*selector) {
                char *next;
#endif
                selector = skip_whitespace(selector);
#if ENABLE_FEATURE_NAMEIF_EXTENDED
                if (*selector == '\0')
                        break;
                /* Search for the end .... */
                next = skip_non_whitespace(selector);
                if (*next)
                        *next++ = '\0';
                /* Check for selectors, mac= is assumed */
                if (strncmp(selector, "bus=", 4) == 0) {
                        ch->bus_info = xstrdup(selector + 4);
                        found_selector++;
                } else if (strncmp(selector, "driver=", 7) == 0) {
                        ch->driver = xstrdup(selector + 7);
                        found_selector++;
                } else {
#endif
                        lmac = xmalloc(ETH_ALEN);
                        ch->mac = ether_aton_r(selector + (strncmp(selector, "mac=", 4) ? 0 : 4), lmac);
                        if (ch->mac == NULL)
                                bb_error_msg_and_die("cannot parse %s", selector);
#if  ENABLE_FEATURE_NAMEIF_EXTENDED
                        found_selector++;
                };
                selector = next;
        }
        if (found_selector == 0)
                bb_error_msg_and_die("no selectors found for %s", ch->ifname);
#endif
}

static void prepend_new_eth_table(ethtable_t **clist, char *ifname, char *selector)
{
        ethtable_t *ch;
        if (strlen(ifname) >= IFNAMSIZ)
                bb_error_msg_and_die("interface name '%s' too long", ifname);
        ch = xzalloc(sizeof(*ch));
        ch->ifname = xstrdup(ifname);
        nameif_parse_selector(ch, selector);
        ch->next = *clist;
        if (*clist)
                (*clist)->prev = ch;
        *clist = ch;
}

#if ENABLE_FEATURE_CLEAN_UP
static void delete_eth_table(ethtable_t *ch)
{
        free(ch->ifname);
#if ENABLE_FEATURE_NAMEIF_EXTENDED
        free(ch->bus_info);
        free(ch->driver);
#endif
        free(ch->mac);
        free(ch);
};
#else
void delete_eth_table(ethtable_t *ch);
#endif

int nameif_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int nameif_main(int argc, char **argv)
{
        ethtable_t *clist = NULL;
        const char *fname = "/etc/mactab";
        int ctl_sk;
        ethtable_t *ch;
        parser_t *parser;
        char *token[2];

        if (1 & getopt32(argv, "sc:", &fname)) {
                openlog(applet_name, 0, LOG_LOCAL0);
                /* Why not just "="? I assume logging to stderr
                 * can't hurt. 2>/dev/null if you don't like it: */
                logmode |= LOGMODE_SYSLOG;
        }
        argc -= optind;
        argv += optind;

        if (argc & 1)
                bb_show_usage();

        if (argc) {
                while (*argv) {
                        char *ifname = xstrdup(*argv++);
                        prepend_new_eth_table(&clist, ifname, *argv++);
                }
        } else {
                parser = config_open(fname);
                while (config_read(parser, token, 2, 2, "# \t", PARSE_NORMAL))
                        prepend_new_eth_table(&clist, token[0], token[1]);
                config_close(parser);
        }

        ctl_sk = xsocket(PF_INET, SOCK_DGRAM, 0);
        parser = config_open2("/proc/net/dev", xfopen_for_read);

        while (clist && config_read(parser, token, 2, 2, "\0: \t", PARSE_NORMAL)) {
                struct ifreq ifr;
#if  ENABLE_FEATURE_NAMEIF_EXTENDED
                struct ethtool_drvinfo drvinfo;
#endif
                if (parser->lineno < 2)
                        continue; /* Skip the first two lines */

                /* Find the current interface name and copy it to ifr.ifr_name */
                memset(&ifr, 0, sizeof(struct ifreq));
                strncpy_IFNAMSIZ(ifr.ifr_name, token[0]);

#if ENABLE_FEATURE_NAMEIF_EXTENDED
                /* Check for driver etc. */
                memset(&drvinfo, 0, sizeof(struct ethtool_drvinfo));
                drvinfo.cmd = ETHTOOL_GDRVINFO;
                ifr.ifr_data = (caddr_t) &drvinfo;
                /* Get driver and businfo first, so we have it in drvinfo */
                ioctl(ctl_sk, SIOCETHTOOL, &ifr);
#endif
                ioctl(ctl_sk, SIOCGIFHWADDR, &ifr);

                /* Search the list for a matching device */
                for (ch = clist; ch; ch = ch->next) {
#if ENABLE_FEATURE_NAMEIF_EXTENDED
                        if (ch->bus_info && strcmp(ch->bus_info, drvinfo.bus_info) != 0)
                                continue;
                        if (ch->driver && strcmp(ch->driver, drvinfo.driver) != 0)
                                continue;
#endif
                        if (ch->mac && memcmp(ch->mac, ifr.ifr_hwaddr.sa_data, ETH_ALEN) != 0)
                                continue;
                        /* if we came here, all selectors have matched */
                        break;
                }
                /* Nothing found for current interface */
                if (!ch)
                        continue;

                if (strcmp(ifr.ifr_name, ch->ifname) != 0) {
                        strcpy(ifr.ifr_newname, ch->ifname);
                        ioctl_or_perror_and_die(ctl_sk, SIOCSIFNAME, &ifr,
                                        "cannot change ifname %s to %s",
                                        ifr.ifr_name, ch->ifname);
                }
                /* Remove list entry of renamed interface */
                if (ch->prev != NULL)
                        ch->prev->next = ch->next;
                else
                        clist = ch->next;
                if (ch->next != NULL)
                        ch->next->prev = ch->prev;
                if (ENABLE_FEATURE_CLEAN_UP)
                        delete_eth_table(ch);
        }
        if (ENABLE_FEATURE_CLEAN_UP) {
                for (ch = clist; ch; ch = ch->next)
                        delete_eth_table(ch);
                config_close(parser);
        };

        return 0;
}