Server unicast option support

diff --git a/src/dhcpv6.c b/src/dhcpv6.c
index 9b03227e0482352476ba497f7f4fabb4bc90033c..b727818139a1aba2f5fffd9032a9a26856a6be26 100644 (file)
--- a/src/dhcpv6.c
+++ b/src/dhcpv6.c
@@ -26,6 +26,7 @@
 #include <sys/time.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
+#include <arpa/inet.h>
 #include <netinet/in.h>
 
 #include <net/if.h>
@@ -95,6 +96,8 @@ static int64_t t1 = 0, t2 = 0, t3 = 0;
 static int request_prefix = -1;
 static enum odhcp6c_ia_mode na_mode = IA_MODE_NONE, pd_mode = IA_MODE_NONE;
 static bool accept_reconfig = false;
+// Server unicast address
+static struct in6_addr server_addr = IN6ADDR_ANY_INIT;
 
 // Reconfigure key
 static uint8_t reconf_key[16];
@@ -156,6 +159,7 @@ int init_dhcpv6(const char *ifname, int request_pd, int sol_timeout)
                        htons(DHCPV6_OPT_SIP_SERVER_A),
                        htons(DHCPV6_OPT_DNS_SERVERS),
                        htons(DHCPV6_OPT_DNS_DOMAIN),
+                       htons(DHCPV6_OPT_UNICAST),
                        htons(DHCPV6_OPT_NTP_SERVER),
                        htons(DHCPV6_OPT_AFTR_NAME),
                        htons(DHCPV6_OPT_PD_EXCLUDE),
@@ -371,7 +375,29 @@ static void dhcpv6_send(enum dhcpv6_msg type, uint8_t trid[3], uint32_t ecs)
                0, ALL_DHCPV6_RELAYS, ifindex};
        struct msghdr msg = {&srv, sizeof(srv), iov, cnt, NULL, 0, 0};
 
-       sendmsg(sock, &msg, 0);
+       switch (type) {
+       case DHCPV6_MSG_REQUEST:
+       case DHCPV6_MSG_RENEW:
+       case DHCPV6_MSG_RELEASE:
+       case DHCPV6_MSG_DECLINE:
+               if (!IN6_IS_ADDR_UNSPECIFIED(&server_addr) &&
+                       odhcp6c_addr_in_scope(&server_addr)) {
+                       srv.sin6_addr = server_addr;
+                       if (!IN6_IS_ADDR_LINKLOCAL(&server_addr))
+                               srv.sin6_scope_id = 0;
+               }
+               break;
+       default:
+               break;
+       }
+
+       if (sendmsg(sock, &msg, 0) < 0) {
+               char in6_str[INET6_ADDRSTRLEN];
+
+               syslog(LOG_ERR, "Failed to send DHCPV6 message to %s (%s)",
+                       inet_ntop(AF_INET6, (const void *)&srv.sin6_addr,
+                               in6_str, sizeof(in6_str)), strerror(errno));
+       }
 }
 
 
@@ -653,7 +679,8 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
 {
        uint16_t olen, otype;
        uint8_t *odata, pref = 0;
-       struct dhcpv6_server_cand cand = {false, false, 0, 0, {0}, NULL, NULL, 0, 0};
+       struct dhcpv6_server_cand cand = {false, false, 0, 0, {0},
+                                       IN6ADDR_ANY_INIT, NULL, NULL, 0, 0};
        bool have_na = false;
        int have_pd = 0;
 
@@ -691,6 +718,8 @@ static int dhcpv6_handle_advert(enum dhcpv6_msg orig, const int rc,
                } else if (otype == DHCPV6_OPT_PREF && olen >= 1 &&
                                cand.preference >= 0) {
                        cand.preference = pref = odata[0];
+               } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(cand.server_addr)) {
+                       cand.server_addr = *(struct in6_addr *)odata;
                } else if (otype == DHCPV6_OPT_RECONF_ACCEPT) {
                        cand.wants_reconfigure = true;
                } else if (otype == DHCPV6_OPT_IA_PD && request_prefix) {
@@ -765,6 +794,7 @@ static int dhcpv6_commit_advert(void)
                odhcp6c_add_state(STATE_SERVER_ID, hdr, sizeof(hdr));
                odhcp6c_add_state(STATE_SERVER_ID, c->duid, c->duid_len);
                accept_reconfig = c->wants_reconfigure;
+               server_addr = c->server_addr;
                if (c->ia_na_len)
                        odhcp6c_add_state(STATE_IA_NA, c->ia_na, c->ia_na_len);
                if (c->ia_pd_len)
@@ -884,6 +914,8 @@ static int dhcpv6_handle_reply(enum dhcpv6_msg orig, _unused const int rc,
                                continue;
 
                        dhcpv6_parse_ia(ia_hdr, odata + olen + sizeof(*ia_hdr));
+               } else if (otype == DHCPV6_OPT_UNICAST && olen == sizeof(server_addr)) {
+                       server_addr = *(struct in6_addr *)odata;
                } else if (otype == DHCPV6_OPT_STATUS && olen >= 2) {
                        uint8_t *mdata = (olen > 2) ? &odata[2] : NULL;
                        uint16_t mlen = (olen > 2) ? olen - 2 : 0;
@@ -1163,7 +1195,18 @@ static void dhcpv6_handle_status_code(const enum dhcpv6_msg orig,
                break;
 
        case DHCPV6_UseMulticast:
-               // TODO handle multicast status code
+               switch(orig) {
+               case DHCPV6_MSG_REQUEST:
+               case DHCPV6_MSG_RENEW:
+               case DHCPV6_MSG_RELEASE:
+               case DHCPV6_MSG_DECLINE:
+                       // Message needs to be retransmitted according to RFC3315 chapter 18.1.8
+                       server_addr = in6addr_any;
+                       *ret = 0;
+                       break;
+               default:
+                       break;
+               }
                break;
 
        case DHCPV6_NoAddrsAvail:

diff --git a/src/odhcp6c.c b/src/odhcp6c.c
index de03b814f95efa86bde343374a14b6769e04cd02..460f230fb3811cac66305ce6467455f40bd313bd 100644 (file)
--- a/src/odhcp6c.c
+++ b/src/odhcp6c.c
@@ -14,6 +14,7 @@
 
 #include <time.h>
 #include <errno.h>
+#include <ctype.h>
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -22,12 +23,14 @@
 #include <syslog.h>
 #include <signal.h>
 #include <string.h>
+#include <strings.h>
 #include <stdbool.h>
 
 #include <net/if.h>
 #include <sys/wait.h>
 #include <sys/syscall.h>
 #include <arpa/inet.h>
+#include <linux/if_addr.h>
 
 #include "odhcp6c.h"
 #include "ra.h"
@@ -36,6 +39,11 @@
 #include "bfd.h"
 #endif
 
+#ifndef IN6_IS_ADDR_UNIQUELOCAL
+#define IN6_IS_ADDR_UNIQUELOCAL(a) \
+       ((((__const uint32_t *) (a))[0] & htonl (0xfe000000)) \
+        == htonl (0xfc000000))
+#endif
 
 static void sighandler(int signal);
 static int usage(void);
@@ -47,7 +55,7 @@ static volatile int do_signal = 0;
 static int urandom_fd = -1, allow_slaac_only = 0;
 static bool bound = false, release = true;
 static time_t last_update = 0;
-
+static char *ifname = NULL;
 
 int main(_unused int argc, char* const argv[])
 {
@@ -171,7 +179,7 @@ int main(_unused int argc, char* const argv[])
        }
 
        openlog("odhcp6c", logopt, LOG_DAEMON);
-       const char *ifname = argv[optind];
+       ifname = argv[optind];
 
        if (help || !ifname)
                return usage();
@@ -585,11 +593,64 @@ void odhcp6c_random(void *buf, size_t len)
        read(urandom_fd, buf, len);
 }
 
+
 bool odhcp6c_is_bound(void)
 {
        return bound;
 }
 
+
+bool odhcp6c_addr_in_scope(const struct in6_addr *addr)
+{
+       FILE *fd = fopen("/proc/net/if_inet6", "r");
+       int len;
+       char buf[256];
+
+       if (fd == NULL)
+               return false;
+
+       while (fgets(buf, sizeof(buf), fd)) {
+               struct in6_addr inet6_addr;
+               uint32_t flags, dummy;
+               unsigned int i;
+               char name[8], addr_buf[32];
+
+               len = strlen(buf);
+
+               if ((len <= 0) || buf[len - 1] != '\n')
+                       return false;
+
+               buf[--len] = '\0';
+
+               if (sscanf(buf, "%s %x %x %x %x %s",
+                               addr_buf, &dummy, &dummy, &dummy, &flags, name) != 6)
+                       return false;
+
+               if (strcmp(name, ifname) ||
+                       (flags & (IFA_F_DADFAILED | IFA_F_TENTATIVE | IFA_F_DEPRECATED)))
+                       continue;
+
+               for (i = 0; i < sizeof(addr_buf); i++) {
+                       if (!isxdigit(addr_buf[i]) || isupper(addr_buf[i]))
+                               return false;
+               }
+
+               memset(&inet6_addr, 0, sizeof(inet6_addr));
+               for (i = 0; i < (sizeof(addr_buf) / 2); i++) {
+                       unsigned char byte;
+                       static const char hex[] = "0123456789abcdef";
+                       byte = ((index(hex, addr_buf[i * 2]) - hex) << 4) |
+                               (index(hex, addr_buf[i * 2 + 1]) - hex);
+                       inet6_addr.s6_addr[i] = byte;
+               }
+
+               if ((IN6_IS_ADDR_LINKLOCAL(&inet6_addr) == IN6_IS_ADDR_LINKLOCAL(addr)) &&
+                       (IN6_IS_ADDR_UNIQUELOCAL(&inet6_addr) == IN6_IS_ADDR_UNIQUELOCAL(addr)))
+                       return true;
+       }
+       return false;
+}
+
 static void sighandler(int signal)
 {
        if (signal == SIGCHLD)

diff --git a/src/odhcp6c.h b/src/odhcp6c.h
index 1a4fbcef9d893448375b0329938e4684ac7a6216..cf8ff741bc2759740192c89b9c291efb87917cfb 100644 (file)
--- a/src/odhcp6c.h
+++ b/src/odhcp6c.h
@@ -34,6 +34,7 @@ enum dhcvp6_opt {
        DHCPV6_OPT_ELAPSED = 8,
        DHCPV6_OPT_RELAY_MSG = 9,
        DHCPV6_OPT_AUTH = 11,
+       DHCPV6_OPT_UNICAST = 12,
        DHCPV6_OPT_STATUS = 13,
        DHCPV6_OPT_RAPID_COMMIT = 14,
        DHCPV6_OPT_RECONF_MESSAGE = 19,
@@ -164,6 +165,7 @@ struct dhcpv6_server_cand {
        int16_t preference;
        uint8_t duid_len;
        uint8_t duid[130];
+       struct in6_addr server_addr;
        void *ia_na;
        void *ia_pd;
        size_t ia_na_len;
@@ -245,6 +247,7 @@ bool odhcp6c_signal_process(void);
 uint64_t odhcp6c_get_milli_time(void);
 void odhcp6c_random(void *buf, size_t len);
 bool odhcp6c_is_bound(void);
+bool odhcp6c_addr_in_scope(const struct in6_addr *addr);
 
 // State manipulation
 void odhcp6c_clear_state(enum odhcp6c_state state);