Add contrib/lease-tools/dhcp_release6

3 files changed, 456 insertions, 2 deletions

diff --git a/contrib/lease-tools/Makefile b/contrib/lease-tools/Makefile
index 68e8d32..f38f2ed 100644
--- a/contrib/lease-tools/Makefile
+++ b/contrib/lease-tools/Makefile
@@ -1,6 +1,6 @@
 CFLAGS?= -O2 -Wall -W
 
-all: dhcp_release dhcp_lease_time
+all: dhcp_release dhcp_release6 dhcp_lease_time
 
 clean:
-	rm -f *~ *.o core dhcp_release dhcp_lease_time
+	rm -f *~ *.o core dhcp_release dhcp_release6 dhcp_lease_time
diff --git a/contrib/lease-tools/dhcp_release6.1 b/contrib/lease-tools/dhcp_release6.1
new file mode 100644
index 0000000..763e01c
--- /dev/null
+++ b/contrib/lease-tools/dhcp_release6.1
@@ -0,0 +1,38 @@
+.TH DHCP_RELEASE 1
+.SH NAME
+dhcp_release6 \- Release a DHCPv6 lease on a the local dnsmasq DHCP server.
+.SH SYNOPSIS
+.B dhcp_release6 --iface <interface> --client-id <client-id> --server-id
+server-id --iaid <iaid>  --ip <IP>  [--dry-run] [--help]
+.SH "DESCRIPTION"
+A utility which forces the DHCP server running on this machine to release a 
+DHCPv6 lease.
+.SS OPTIONS
+.IP "-a, --ip"
+IPv6 address to release.
+.IP "-c, --client-id"
+Colon-separated hex string representing DHCPv6 client id. Normally
+it can be found in leases file both on client and server.
+.IP "-d, --dry-run"
+Print hexadecimal representation of generated DHCPv6 release packet to standard
+output and exit.
+.IP "-h, --help"
+print usage information to standard output and exit.
+.IP "-i, --iaid"
+Decimal representation of DHCPv6 IAID. Normally it can be found in leases file
+both on client and server.
+.IP "-n, --iface"
+Network interface to send a DHCPv6 release packet from.
+.IP "-s, --server-id"
+Colon-separated hex string representing DHCPv6 server id. Normally
+it can be found in leases file both on client and server.
+.SH NOTES
+MUST be run as root - will fail otherwise.
+.SH LIMITATIONS
+Only usable on IPv6 DHCP leases.
+.SH SEE ALSO
+.BR dnsmasq (8)
+.SH AUTHOR
+This manual page was written by Simon Kelley <simon@thekelleys.org.uk>.
+
+
diff --git a/contrib/lease-tools/dhcp_release6.c b/contrib/lease-tools/dhcp_release6.c
new file mode 100644
index 0000000..74fb26a
--- /dev/null
+++ b/contrib/lease-tools/dhcp_release6.c
@@ -0,0 +1,416 @@
+/*
+ dhcp_release6 --iface <interface> --client-id <client-id> --server-id
+ server-id --iaid <iaid>  --ip <IP>  [--dry-run] [--help]
+ MUST be run as root - will fail othewise
+ */
+
+/* Send a DHCPRELEASE message  to IPv6 multicast address  via the specified interface
+ to tell the local DHCP server to delete a particular lease.
+ 
+ The interface argument is the interface in which a DHCP
+ request _would_ be received if it was coming from the client,
+ rather than being faked up here.
+ 
+ The client-id argument is colon-separated hex string and mandatory. Normally
+ it can be found in leases file both on client and server
+
+ The server-id argument is colon-separated hex string and mandatory. Normally
+ it can be found in leases file both on client and server.
+ 
+ The iaid argument is numeric string and mandatory. Normally
+ it can be found in leases file both on client and server.
+ 
+ IP is an IPv6 adress to release
+ 
+ If --dry-run is specified, dhcp_release6 just prints hexadecimal represantation of
+ packet to send to stdout and exits.
+ 
+ If --help is specified, dhcp_release6 print usage information to stdout and exits
+ 
+ 
+ 
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <getopt.h>
+#include <errno.h>
+#include <unistd.h>
+
+#define NOT_REPLY_CODE 115
+typedef unsigned char u8;
+typedef unsigned short u16;
+typedef unsigned int u32;
+
+enum DHCP6_TYPES{
+    SOLICIT = 1,
+    ADVERTISE = 2,
+    REQUEST = 3,
+    CONFIRM = 4,
+    RENEW = 5,
+    REBIND = 6,
+    REPLY = 7,
+    RELEASE = 8,
+    DECLINE = 9,
+    RECONFIGURE = 10,
+    INFORMATION_REQUEST = 11,
+    RELAY_FORW = 12,
+    RELAY_REPL = 13
+    
+};
+enum DHCP6_OPTIONS{
+    CLIENTID = 1,
+    SERVERID = 2,
+    IA_NA = 3,
+    IA_TA = 4,
+    IAADDR = 5,
+    ORO = 6,
+    PREFERENCE = 7,
+    ELAPSED_TIME = 8,
+    RELAY_MSG = 9,
+    AUTH = 11,
+    UNICAST = 12,
+    STATUS_CODE = 13,
+    RAPID_COMMIT = 14,
+    USER_CLASS = 15,
+    VENDOR_CLASS = 16,
+    VENDOR_OPTS = 17,
+    INTERFACE_ID = 18,
+    RECONF_MSG = 19,
+    RECONF_ACCEPT = 20,
+};
+
+enum DHCP6_STATUSES{
+    SUCCESS = 0,
+    UNSPEC_FAIL = 1,
+    NOADDR_AVAIL=2,
+    NO_BINDING  = 3,
+    NOT_ON_LINK = 4,
+    USE_MULTICAST =5
+};
+static struct option longopts[] = {
+    {"ip", required_argument, 0, 'a'},
+    {"server-id", required_argument, 0, 's'},
+    {"client-id", required_argument, 0, 'c'},
+    {"iface", required_argument, 0, 'n'},
+    {"iaid", required_argument, 0, 'i'},
+    {"dry-run", no_argument, 0, 'd'},
+    {"help", no_argument, 0, 'h'},
+    {0,     0,           0,   0}
+};
+
+const short DHCP6_CLIENT_PORT = 546;
+const short DHCP6_SERVER_PORT = 547;
+
+const char*  DHCP6_MULTICAST_ADDRESS = "ff02::1:2";
+
+struct dhcp6_option{
+    uint16_t type;
+    uint16_t len;
+    char  value[1024];
+};
+
+struct dhcp6_iaaddr_option{
+    uint16_t type;
+    uint16_t len;
+    struct in6_addr ip;
+    uint32_t preferred_lifetime;
+    uint32_t valid_lifetime;
+    
+    
+};
+
+struct dhcp6_iana_option{
+    uint16_t type;
+    uint16_t len;
+    uint32_t iaid;
+    uint32_t t1;
+    uint32_t t2;
+    char options[1024];
+};
+
+
+struct dhcp6_packet{
+    size_t len;
+    char buf[2048];
+    
+} ;
+
+size_t pack_duid(const char* str, char* dst){
+    
+    char* tmp = strdup(str);
+    char* tmp_to_free = tmp;
+    char *ptr;
+    uint8_t write_pos = 0;
+    while ((ptr = strtok (tmp, ":"))) {
+        dst[write_pos] = (uint8_t) strtol(ptr, NULL, 16);
+        write_pos += 1;
+        tmp = NULL;
+        
+    }
+    free(tmp_to_free);
+    return write_pos;
+}
+
+struct dhcp6_option create_client_id_option(const char* duid){
+    struct dhcp6_option option;
+    option.type = htons(CLIENTID);
+    bzero(option.value, sizeof(option.value));
+    option.len  = htons(pack_duid(duid, option.value));
+    return option;
+}
+
+struct dhcp6_option create_server_id_option(const char* duid){
+    struct dhcp6_option   option;
+    option.type = htons(SERVERID);
+    bzero(option.value, sizeof(option.value));
+    option.len  = htons(pack_duid(duid, option.value));
+    return option;
+}
+
+struct dhcp6_iaaddr_option create_iaadr_option(const char* ip){
+    struct dhcp6_iaaddr_option result;
+    result.type =htons(IAADDR);
+    /* no suboptions needed here, so length is 24  */
+    result.len = htons(24);
+    result.preferred_lifetime = 0;
+    result.valid_lifetime = 0;
+    int s = inet_pton(AF_INET6, ip, &(result.ip));
+    if (s <= 0) {
+        if (s == 0)
+            fprintf(stderr, "Not in presentation format");
+        else
+            perror("inet_pton");
+        exit(EXIT_FAILURE);
+    }
+    return result;
+}
+struct dhcp6_iana_option  create_iana_option(const char * iaid, struct dhcp6_iaaddr_option  ia_addr){
+    struct dhcp6_iana_option  result;
+    result.type = htons(IA_NA);
+    result.iaid = htonl(atoi(iaid));
+    result.t1 = 0;
+    result.t2 = 0;
+    result.len = htons(12 + ntohs(ia_addr.len) + 2 * sizeof(uint16_t));
+    memcpy(result.options, &ia_addr, ntohs(ia_addr.len) + 2 * sizeof(uint16_t));
+    return result;
+}
+
+struct dhcp6_packet create_release_packet(const char* iaid, const char* ip, const char* client_id, const char* server_id){
+    struct dhcp6_packet result;
+    bzero(result.buf, sizeof(result.buf));
+    /* message_type */
+    result.buf[0] = RELEASE;
+    /* tx_id */
+    bzero(result.buf+1, 3);
+    
+    struct dhcp6_option client_option = create_client_id_option(client_id);
+    struct dhcp6_option server_option = create_server_id_option(server_id);
+    struct dhcp6_iaaddr_option iaaddr_option = create_iaadr_option(ip);
+    struct dhcp6_iana_option iana_option = create_iana_option(iaid, iaaddr_option);
+    int offset = 4;
+    memcpy(result.buf + offset, &client_option, ntohs(client_option.len) + 2*sizeof(uint16_t));
+    offset += (ntohs(client_option.len)+ 2 *sizeof(uint16_t) );
+    memcpy(result.buf + offset, &server_option, ntohs(server_option.len) + 2*sizeof(uint16_t) );
+    offset += (ntohs(server_option.len)+ 2* sizeof(uint16_t));
+    memcpy(result.buf + offset, &iana_option, ntohs(iana_option.len) + 2*sizeof(uint16_t) );
+    offset += (ntohs(iana_option.len)+ 2* sizeof(uint16_t));
+    result.len = offset;
+    return result;
+}
+
+uint16_t parse_iana_suboption(char* buf, size_t len){
+    size_t current_pos = 0;
+    char option_value[1024];
+    while (current_pos < len) {
+        uint16_t option_type, option_len;
+        memcpy(&option_type,buf + current_pos, sizeof(uint16_t));
+        memcpy(&option_len,buf + current_pos + sizeof(uint16_t), sizeof(uint16_t));
+        option_type = ntohs(option_type);
+        option_len = ntohs(option_len);
+        current_pos += 2 * sizeof(uint16_t);
+        if (option_type == STATUS_CODE){
+            uint16_t status;
+            memcpy(&status, buf + current_pos, sizeof(uint16_t));
+            status = ntohs(status);
+            if (status != SUCCESS){
+                memcpy(option_value, buf + current_pos + sizeof(uint16_t) , option_len - sizeof(uint16_t));
+                option_value[option_len-sizeof(uint16_t)] ='\0';
+                fprintf(stderr, "Error: %s\n", option_value);
+            }
+            return status;
+        }
+    }
+    return -2;
+}
+
+int16_t parse_packet(char* buf, size_t len){
+    uint8_t type  = buf[0];
+    /*skipping tx id. you need it, uncomment following line
+        uint16_t tx_id = ntohs((buf[1] <<16) + (buf[2] <<8) + buf[3]);
+     */
+    size_t current_pos = 4;
+    if (type != REPLY ){
+        return NOT_REPLY_CODE;
+    }
+    char option_value[1024];
+    while (current_pos < len) {
+        uint16_t option_type, option_len;
+        memcpy(&option_type,buf + current_pos, sizeof(uint16_t));
+        memcpy(&option_len,buf + current_pos + sizeof(uint16_t), sizeof(uint16_t));
+        option_type = ntohs(option_type);
+        option_len = ntohs(option_len);
+        current_pos += 2 * sizeof(uint16_t);
+        if (option_type == STATUS_CODE){
+            uint16_t status;
+            memcpy(&status, buf + current_pos, sizeof(uint16_t));
+            status = ntohs(status);
+            if (status != SUCCESS){
+                memcpy(option_value, buf + current_pos +sizeof(uint16_t) , option_len -sizeof(uint16_t));
+                fprintf(stderr, "Error: %d %s\n", status, option_value);
+                return status;
+            }
+            
+        }
+        if (option_type == IA_NA ){
+            uint16_t result = parse_iana_suboption(buf + current_pos +24, option_len -24);
+            if (result){
+                return result;
+            }
+        }
+        current_pos += option_len;
+
+    }
+    return -1;
+}
+
+void usage(const char* arg, FILE* stream){
+    const char* usage_string ="--ip IPv6 --iface IFACE --server-id SERVER_ID --client-id CLIENT_ID --iaid IAID [--dry-run] | --help";
+    fprintf (stream, "Usage: %s %s\n", arg, usage_string);
+    
+}
+
+int send_release_packet(const char* iface, struct dhcp6_packet* packet){
+    
+    struct sockaddr_in6 server_addr, client_addr;
+    char response[1400];
+    int sock = socket(PF_INET6, SOCK_DGRAM, 0);
+    int i = 0;
+    if (sock < 0) {
+        perror("creating socket");
+        return -1;
+    }
+    if (setsockopt(sock, SOL_SOCKET, 25, iface, strlen(iface)) == -1)  {
+        perror("SO_BINDTODEVICE");
+        close(sock);
+        return -1;
+    }
+    memset(&server_addr, 0, sizeof(server_addr));
+    server_addr.sin6_family = AF_INET6;
+    client_addr.sin6_family = AF_INET6;
+    client_addr.sin6_port = htons(DHCP6_CLIENT_PORT);
+    client_addr.sin6_flowinfo = 0;
+    client_addr.sin6_scope_id =0;
+    inet_pton(AF_INET6, "::", &client_addr.sin6_addr);
+    bind(sock, (struct sockaddr*)&client_addr, sizeof(struct sockaddr_in6));
+    inet_pton(AF_INET6, DHCP6_MULTICAST_ADDRESS, &server_addr.sin6_addr);
+    server_addr.sin6_port = htons(DHCP6_SERVER_PORT);
+    int16_t recv_size = 0;
+    for (i = 0; i < 5; i++) {
+        if (sendto(sock, packet->buf, packet->len, 0,
+               (struct sockaddr *)&server_addr,
+               sizeof(server_addr)) < 0) {
+            perror("sendto failed");
+            exit(4);
+        }
+        recv_size = recvfrom(sock, response, sizeof(response), MSG_DONTWAIT, NULL, 0);
+        if (recv_size == -1){
+            if (errno == EAGAIN){
+                sleep(1);
+                continue;
+            }else {
+                perror("recvfrom");
+            }
+        }
+        int16_t result = parse_packet(response, recv_size);
+        if (result == NOT_REPLY_CODE){
+            sleep(1);
+            continue;
+        }
+        return result;
+    }
+    fprintf(stderr, "Response timed out\n");
+    return -1;
+    
+}
+
+
+int main(int argc, char *  const argv[]) {
+    const char* iface = "";
+    const char* ip = "";
+    const char* client_id = "";
+    const char* server_id = "";
+    const char* iaid = "";
+    int dry_run = 0;
+    while (1) {
+        int option_index = 0;
+        int c = getopt_long(argc, argv, "a:s:c:n:i:hd", longopts, &option_index);
+        if (c == -1){
+            break;
+        }
+        switch(c){
+            case 0:
+                if (longopts[option_index].flag !=0){
+                    break;
+                }
+                printf ("option %s", longopts[option_index].name);
+                if (optarg)
+                    printf (" with arg %s", optarg);
+                printf ("\n");
+                break;
+            case 'i':
+                iaid = optarg;
+                break;
+            case 'n':
+                iface = optarg;
+                break;
+            case 'a':
+                ip = optarg;
+                break;
+            case 'c':
+                client_id = optarg;
+                break;
+            case 'd':
+                dry_run = 1;
+                break;
+            case 's':
+                server_id = optarg;
+                break;
+            case 'h':
+                usage(argv[0], stdout);
+                break;
+            case '?':
+                usage(argv[0], stderr);
+                return -1;
+             default:
+                abort();
+                
+        }
+        
+    }
+    struct dhcp6_packet packet = create_release_packet(iaid, ip, client_id, server_id);
+    if (dry_run){
+        uint16_t i;
+        for(i=0;i<packet.len;i++){
+            printf("%hhx", packet.buf[i]);
+        }
+        printf("\n");
+        return 0;
+    }
+    return send_release_packet(iface, &packet);
+    
+}