klibc-utils: add ipconfig.c work-in-progress

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 316 insertions, 0 deletions

diff --git a/klibc-utils/ipconfig.c.txt b/klibc-utils/ipconfig.c.txt
new file mode 100644
index 000000000..5dd95c16b
--- /dev/null
+++ b/klibc-utils/ipconfig.c.txt
@@ -0,0 +1,316 @@
+/*
+ * Copyright (c) 2017 Denys Vlasenko <vda.linux@googlemail.com>
+ *
+ * Licensed under GPLv2, see file LICENSE in this source tree.
+ */
+//config:config IPCONFIG
+//config:       bool "ipconfig"
+//config:       default y
+//config:       help
+//config:       (Auto)configure network.
+
+//applet:IF_IPCONFIG(APPLET(ipconfig, BB_DIR_BIN, BB_SUID_DROP))
+
+//kbuild:lib-$(CONFIG_IPCONFIG) += ipconfig.o
+
+#include <net/if.h>
+#include "libbb.h"
+
+struct globals {
+        int fixed;
+        const char *hostname;
+};
+#define G (*ptr_to_globals)
+#define INIT_G() do { \
+        SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
+} while (0)
+
+struct dev {
+        const char *name;
+        uint8_t  fixed;
+        uint32_t ip_addr;
+        uint32_t ip_netmask;
+        uint32_t ip_server;
+        uint32_t ip_router;
+};
+
+static int
+parse_method(const char *method)
+{
+        int fixed;
+
+        fixed = (method[0] != '\0');
+        if (fixed) {
+                /* if it's not "" */
+                fixed = index_in_strings(
+                        /* 0 */ "on""\0"
+                        /* 1 */ "any""\0"
+                        /* 2 */ "both""\0"
+                        /* 3 */ "dhcp""\0"
+                        /* 4 */ "bootp""\0"
+                        /* 5 */ "rarp""\0"
+                        /* 6 */ "none""\0"
+                        /* 7 */ "static""\0"
+                        /* 8 */ "off""\0"
+                        , method
+                );
+                if (fixed > 0)
+                        fixed /= 6;
+        }
+        return fixed;
+}
+
+static uint32_t
+parse_addr(const char *ip)
+{
+        struct in_addr in;
+        if (inet_aton(ip, &in) == 0)
+                bb_error_msg_and_die("bad IP address '%s'", ip);
+        return in.s_addr;
+}
+
+static struct dev*
+find_device(llist_t *iface_list, const char *name)
+{
+        while (iface_list) {
+                struct dev *dev = (void*) iface_list->data;
+                if (strcmp(dev->name, name) == 0)
+                        return dev;
+                iface_list = iface_list->link;
+        }
+        return NULL;
+}
+
+static void
+set_from_template(struct dev *dev, struct dev *template)
+{
+        if (template->ip_addr != 0)
+                dev->ip_addr = template->ip_addr;
+        if (template->ip_netmask != 0)
+                dev->ip_netmask = template->ip_netmask;
+        if (template->ip_server != 0)
+                dev->ip_server = template->ip_server;
+        if (template->ip_router != 0)
+                dev->ip_router = template->ip_router;
+        dev->fixed = template->fixed;
+}
+
+// "ip=PROTO" - also implies -o
+// "nfsaddrs=PROTO" - also implies -o
+// "<devname>"
+// "[ip=/nfsaddrs=]IP:SERVER_IP:ROUTER:NETMASK:HOSTNAME:IFACE:METHOD"
+// all optional. trailing empty :: can be skipped, only one : needs to be there
+// (to distinguish from other formats).
+// ":::::eth0" - dhcp on eth0
+// ":" - dhcp on all ifaces
+// "::1.2.3.4" - dhcp on all ifaces, gateway is 1.2.3.4 (fairly nonsensical)
+static void
+add_all_devices(llist_t **iface_list, struct dev *template);
+static struct dev*
+add_device(llist_t **iface_list, char *ip)
+{
+        struct dev *dev;
+
+        dev = xzalloc(sizeof(*dev));
+        dev->fixed = G.fixed;
+
+        if (strncmp("ip=", ip, 3) == 0
+         || strncmp("nfsaddrs=", ip, 9) == 0
+        ) {
+                int fixed;
+
+                ip = strchr(ip, '=') + 1;
+                fixed = parse_method(ip);
+                if (fixed >= 0) {
+                        add_all_devices(iface_list, dev);
+                        free(dev);
+                        return NULL;
+                }
+        }
+
+        if (!strchr(ip, ':')) {
+                dev->name = ip;
+        } else {
+                unsigned opt = 0;
+                while (ip && *ip) {
+                        char *next = strchr(ip, ':');
+                        if (next)
+                                *next++ = '\0';
+                        if (opt > 6)
+                                bb_error_msg_and_die("too many options for %s", dev->name);
+                        if (ip[0]) switch (opt) {
+                        case 0:
+                                dev->ip_addr = parse_addr(ip);
+                                break;
+                        case 1:
+                                dev->ip_server = parse_addr(ip);
+                                break;
+                        case 2:
+                                dev->ip_router = parse_addr(ip);
+                                break;
+                        case 3:
+                                dev->ip_netmask = parse_addr(ip);
+                                break;
+                        case 4:
+                                if (G.hostname && strcmp(G.hostname, ip) != 0)
+                                        bb_error_msg_and_die("hostname must be the same");
+                                G.hostname = ip;
+                                break;
+                        case 5:
+                                dev->name = ip;
+                                break;
+                        case 6:
+                                dev->fixed = parse_method(ip);
+                                break;
+                        }
+                        ip = next;
+                        opt++;
+                }
+        }
+
+        if (dev->name == NULL
+         || strcmp(dev->name, "all") == 0
+        ) {
+                add_all_devices(iface_list, dev);
+                free(dev);
+                return NULL;
+        }
+        llist_add_to_end(iface_list, dev);
+        return dev;
+}
+
+static void
+add_all_devices(llist_t **iface_list, struct dev *template)
+{
+        DIR *d;
+        struct dirent *de;
+#define sys_class_net "/sys/class/net"
+
+        /* All forms of "config all ifaces" imply -o */
+        option_mask32 |= 1;
+
+        d = opendir(sys_class_net);
+        if (!d)
+                return;
+
+        while ((de = readdir(d)) != NULL) {
+                struct dev *dev;
+                char *filename;
+                char p[sizeof(long)*3];
+                unsigned long flags;
+                int r;
+
+                /* Exclude devices beginning with dots as well as . and .. */
+                if (de->d_name[0] == '.')
+                        continue;
+                filename = xasprintf("%s/%s/flags", sys_class_net, de->d_name);
+                r = open_read_close(filename, p, sizeof(p) - 1);
+                free(filename);
+                if (r < 0)
+                        continue;
+                p[r] = '\0';
+                /* file's format is "0xNNNN\n" */
+                flags = bb_strtoul(p, NULL, 0);
+                /*
+                 * Heuristic for if this is a reasonable boot interface.
+                 * This is the same logic the in-kernel ipconfig uses.
+                 */
+                if (flags & IFF_LOOPBACK)
+                        continue;
+                if (!(flags & (IFF_BROADCAST | IFF_POINTOPOINT)))
+                        continue;
+                if (find_device(*iface_list, de->d_name))
+                        continue;
+                dev = add_device(iface_list, xstrdup(de->d_name));
+                if (dev)
+                        set_from_template(dev, template);
+        }
+        closedir(d);
+#undef sys_class_net
+}
+
+//usage:#define ipconfig_trivial_usage
+//usage:       "[-c METHOD] [-t TIMEOUT] [-on] [-i VENDOR_ID] [-p PORT] [-d] IFACE..."
+//usage:#define ipconfig_full_usage "\n\n"
+//usage:       "(Auto)configure network"
+//usage:   "\n"
+//usage:   "\n""        -c METHOD       off/none/static or on/dhcp (default)"
+//usage:   "\n""        -t SECONDS      Give up after SECONDS"
+//usage:   "\n""        -o              Stop after one interface is configured"
+//usage:   "\n""        -n              Dry run"
+//usage:   "\n""        -i VENDOR_ID    DHCP vendor id (default '')"
+//usage:   "\n""        -p PORT         DHCP port to use"
+//usage:   "\n""        [-d] IFACE...   Interface(s)"
+//usage:   "\n"
+//usage:   "\n""        IFACE can be:"
+//usage:   "\n""        all - configure all interfaces"
+//usage:   "\n""        IFACE - configure this interface"
+//usage:   "\n""        IP:SERVER_IP:ROUTER:NETMASK:HOSTNAME:IFACE:METHOD (all optional)"
+// TIMEOUT defaults to infinite
+// -d actually is an option with an argument
+// (not a clue why klibc-utils has two ways to specify interfaces)
+int ipconfig_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int ipconfig_main(int argc UNUSED_PARAM, char **argv)
+{
+        const char *method = "";
+        const char *vendor_id = "";
+        llist_t *devname_list = NULL;
+        llist_t *iface_list;
+        int timeout = -1;
+        unsigned port;
+        unsigned opt;
+
+        INIT_G();
+
+        opt = getopt32(argv,
+                "onc:t:i:p:+d:*",
+                &method, &timeout, &vendor_id, &port, &devname_list
+        );
+        argv += optind;
+
+        G.fixed = parse_method(method);
+        if (G.fixed < 0)
+                bb_show_usage();
+
+        iface_list = NULL;
+        while (devname_list)
+                add_device(&iface_list, (char*) llist_pop(&devname_list));
+        while (*argv)
+                add_device(&iface_list, *argv++);
+
+        while (iface_list) {
+                struct dev *dev = (void*) iface_list->data;
+                printf("name:'%s'\n", dev->name);
+                printf("fixed:%u\n" , dev->fixed);
+                printf("ip:%s/"     , inet_ntoa(*(struct in_addr*)&dev->ip_addr));
+                printf("%s\n"       , inet_ntoa(*(struct in_addr*)&dev->ip_netmask));
+                printf("server:%s\n", inet_ntoa(*(struct in_addr*)&dev->ip_server));
+                printf("router:%s\n", inet_ntoa(*(struct in_addr*)&dev->ip_router));
+                iface_list = iface_list->link;
+        }
+        bb_error_msg("hostname:'%s'", G.hostname);
+        bb_error_msg("fixed:%u", G.fixed);
+
+        return EXIT_SUCCESS;
+}
+//After device is configured, write out a "/run/net-IFACE.conf" file:
+//                                                              // udchcp env values:
+//write_option("DEVICE",        dev->name);                     interface=eth0
+//write_option("PROTO",         method);
+//write_option("IPV4ADDR",      dev->ip_addr);                  ip=10.43.17.38
+//write_option("IPV4BROADCAST", dev->ip_broadcast);             subnet=255.255.255.0 mask=24
+//write_option("IPV4NETMASK",   dev->ip_netmask);               subnet=255.255.255.0 mask=24
+//write_option("IPV4GATEWAY",   dev->ip_gateway);               router=10.43.17.254
+//write_option("IPV4DNS0",      dev->ip_nameserver[0]);         dns=10.38.5.26 10.11.5.19
+//write_option("IPV4DNS1",      dev->ip_nameserver[1]);         dns=10.38.5.26 10.11.5.19
+//write_option("HOSTNAME",      dev->hostname);                   hostname="STR"
+//write_option("DNSDOMAIN",     dev->dnsdomainname);            domain=domain.com
+//write_option("NISDOMAIN",     dev->nisdomainname);              nisdomain="STR"
+//write_option("ROOTSERVER",    my_inet_ntoa(dev->ip_server));  serverid=10.44.6.2
+//write_option("ROOTPATH",      dev->bootpath);                   rootpath="STR"
+//write_option("filename",      dev->filename);                 boot_file=/pxelinux.0
+//write_option("UPTIME",        dev->uptime);                     sysinfo()->uptime
+//write_option("DHCPLEASETIME", dev->dhcpleasetime);            lease=44148
+//write_option("DOMAINSEARCH",  dev->domainsearch);             search="ABC DEF"
+//
+//(write_option writes out single-quote escaped string, VAR='VAL')