Re: [B.A.T.M.A.N.] [PATCH v2] [alfred] IPv4 multicast distribution support.

-- Jonathan R. Haws Embedded Engineer Space Dynamics Laboratory jhaws@sdl.usu.edu On Tue, 2017-01-17 at 22:01 -0700, Jonathan Haws wrote: > Enabled via -4 expert option where multicast group address is > specified. > This option will disable IPv6 communication and is intended for use > in > networks which do not support IPv6 addressing. > > When this option is enabled, all IPv6 communication is disabled. > Combining > IPv4 and IPv6 alfred nodes is unsupported. > > Signed-off-by: Jonathan Haws jhaws@sdl.usu.edu > --- >  README         |   4 +- >  alfred.h       |  20 +++++--- >  batadv_query.c |  53 +++++++++++++------- >  batadv_query.h |   5 +- >  client.c       |   2 +- >  main.c         |  14 ++++-- >  man/alfred.8   |   5 ++ >  netsock.c      | 156 > +++++++++++++++++++++++++++++++++++++++++++++++++++++---- >  recv.c         |  61 +++++++++++++++------- >  send.c         |  48 +++++++++++------- >  server.c       |   8 +-- >  unix_sock.c    |   2 +- >  12 files changed, 295 insertions(+), 83 deletions(-) > > diff --git a/README b/README > index bc1c3bc..28f3dc9 100644 > --- a/README > +++ b/README > @@ -20,7 +20,9 @@ programs to communicate with alfred (done via unix > sockets). alfred then takes >  care of distributing the local information to other alfred servers > on other >  nodes. This is done via IPv6 link-local multicast, and does not > require any >  configuration. A user can request data from alfred, and will receive > the > -information available from all alfred servers in the network. > +information available from all alfred servers in the network. > Alternatively, > +alfred can be configured to distribute the local information via > IPv4 multicast. > +This is configured by setting the IPv4 multicast group address in > the -4 option. >   >  Compilation >  ----------- > diff --git a/alfred.h b/alfred.h > index 2e8db1e..bec69a1 100644 > --- a/alfred.h > +++ b/alfred.h > @@ -48,6 +48,11 @@ enum data_source { >   SOURCE_SYNCED = 2, >  }; >   > +typedef union { > + struct in_addr ipv4; > + struct in6_addr ipv6; > +} alfred_addr; > + >  struct dataset { >   struct alfred_data data; >   unsigned char *buf; > @@ -80,7 +85,7 @@ struct transaction_head { >   >  struct server { >   struct ether_addr hwaddr; > - struct in6_addr address; > + alfred_addr address; >   struct timespec last_seen; >   uint8_t tq; >  }; > @@ -100,7 +105,7 @@ enum clientmode { >   >  struct interface { >   struct ether_addr hwaddr; > - struct in6_addr address; > + alfred_addr address; >   uint32_t scope_id; >   char *interface; >   int netsock; > @@ -122,6 +127,7 @@ struct globals { >   int clientmode_arg; >   int clientmode_version; >   int verbose; > + int ipv4mode; >   >   int unix_sock; >   const char *unix_path; > @@ -142,7 +148,7 @@ struct globals { >   >  #define MAX_PAYLOAD ((1 << 16) - 1 - sizeof(struct udphdr)) >   > -extern const struct in6_addr in6addr_localmcast; > +extern alfred_addr alfred_mcast; >   >  /* server.c */ >  int alfred_server(struct globals *globals); > @@ -169,13 +175,13 @@ static inline bool transaction_finished(struct > transaction_head *head) >   >  /* send.c */ >  int push_data(struct globals *globals, struct interface *interface, > -       struct in6_addr *destination, enum data_source > max_source_level, > +       alfred_addr *destination, enum data_source > max_source_level, >         int type_filter, uint16_t tx_id); >  int announce_master(struct globals *globals); >  int push_local_data(struct globals *globals); >  int sync_data(struct globals *globals); > -ssize_t send_alfred_packet(struct interface *interface, > -    const struct in6_addr *dest, void *buf, > int length); > +ssize_t send_alfred_packet(struct globals *globals, struct interface > *interface, > +    const alfred_addr *dest, void *buf, int > length); >  /* unix_sock.c */ >  int unix_sock_read(struct globals *globals); >  int unix_sock_open_daemon(struct globals *globals); > @@ -195,7 +201,7 @@ int netsock_prepare_select(struct globals > *globals, fd_set *fds, int maxsock); >  void netsock_check_error(struct globals *globals, fd_set *errfds); >  int netsock_receive_packet(struct globals *globals, fd_set *fds); >  int netsock_own_address(const struct globals *globals, > - const struct in6_addr *address); > + const alfred_addr *address); >  /* util.c */ >  int time_diff(struct timespec *tv1, struct timespec *tv2, >         struct timespec *tvdiff); > diff --git a/batadv_query.c b/batadv_query.c > index ac45b9b..f616501 100644 > --- a/batadv_query.c > +++ b/batadv_query.c > @@ -80,22 +80,22 @@ out: >   return ret; >  } >   > -int mac_to_ipv6(const struct ether_addr *mac, struct in6_addr *addr) > +int mac_to_ipv6(const struct ether_addr *mac, alfred_addr *addr) >  { >   memset(addr, 0, sizeof(*addr)); > - addr->s6_addr[0] = 0xfe; > - addr->s6_addr[1] = 0x80; > + addr->ipv6.s6_addr[0] = 0xfe; > + addr->ipv6.s6_addr[1] = 0x80; >   > - addr->s6_addr[8] = mac->ether_addr_octet[0] ^ 0x02; > - addr->s6_addr[9] = mac->ether_addr_octet[1]; > - addr->s6_addr[10] = mac->ether_addr_octet[2]; > + addr->ipv6.s6_addr[8] = mac->ether_addr_octet[0] ^ 0x02; > + addr->ipv6.s6_addr[9] = mac->ether_addr_octet[1]; > + addr->ipv6.s6_addr[10] = mac->ether_addr_octet[2]; >   > - addr->s6_addr[11] = 0xff; > - addr->s6_addr[12] = 0xfe; > + addr->ipv6.s6_addr[11] = 0xff; > + addr->ipv6.s6_addr[12] = 0xfe; >   > - addr->s6_addr[13] = mac->ether_addr_octet[3]; > - addr->s6_addr[14] = mac->ether_addr_octet[4]; > - addr->s6_addr[15] = mac->ether_addr_octet[5]; > + addr->ipv6.s6_addr[13] = mac->ether_addr_octet[3]; > + addr->ipv6.s6_addr[14] = mac->ether_addr_octet[4]; > + addr->ipv6.s6_addr[15] = mac->ether_addr_octet[5]; >   >   return 0; >  } > @@ -118,17 +118,32 @@ int is_ipv6_eui64(const struct in6_addr *addr) >   return 1; >  } >   > -int ipv6_to_mac(const struct in6_addr *addr, struct ether_addr *mac) > +int ipv6_to_mac(const alfred_addr *addr, struct ether_addr *mac) >  { > - if (!is_ipv6_eui64(addr)) > + if (!is_ipv6_eui64(&addr->ipv6)) >   return -EINVAL; >   > - mac->ether_addr_octet[0] = addr->s6_addr[8] ^ 0x02; > - mac->ether_addr_octet[1] = addr->s6_addr[9]; > - mac->ether_addr_octet[2] = addr->s6_addr[10]; > - mac->ether_addr_octet[3] = addr->s6_addr[13]; > - mac->ether_addr_octet[4] = addr->s6_addr[14]; > - mac->ether_addr_octet[5] = addr->s6_addr[15]; > + mac->ether_addr_octet[0] = addr->ipv6.s6_addr[8] ^ 0x02; > + mac->ether_addr_octet[1] = addr->ipv6.s6_addr[9]; > + mac->ether_addr_octet[2] = addr->ipv6.s6_addr[10]; > + mac->ether_addr_octet[3] = addr->ipv6.s6_addr[13]; > + mac->ether_addr_octet[4] = addr->ipv6.s6_addr[14]; > + mac->ether_addr_octet[5] = addr->ipv6.s6_addr[15]; > + > + if (!is_valid_ether_addr(mac->ether_addr_octet)) > + return -EINVAL; > + > + return 0; > +} > + > +int ipv4_to_mac(const alfred_addr *addr, struct ether_addr *mac) > +{ > + mac->ether_addr_octet[0] = 0; > + mac->ether_addr_octet[1] = 0; > + mac->ether_addr_octet[2] = (addr->ipv4.s_addr >> 24) & 0xFF; > + mac->ether_addr_octet[3] = (addr->ipv4.s_addr >> 16) & 0xFF; > + mac->ether_addr_octet[4] = (addr->ipv4.s_addr >>  8) & 0xFF; > + mac->ether_addr_octet[5] = (addr->ipv4.s_addr >>  0) & 0xFF; >   >   if (!is_valid_ether_addr(mac->ether_addr_octet)) >   return -EINVAL; > diff --git a/batadv_query.h b/batadv_query.h > index 0df8a35..ec69290 100644 > --- a/batadv_query.h > +++ b/batadv_query.h > @@ -28,8 +28,9 @@ struct ether_addr *translate_mac(const char > *mesh_iface, >    const struct ether_addr *mac); >  uint8_t get_tq(const char *mesh_iface, struct ether_addr *mac); >  int batadv_interface_check(const char *mesh_iface); > -int mac_to_ipv6(const struct ether_addr *mac, struct in6_addr > *addr); > -int ipv6_to_mac(const struct in6_addr *addr, struct ether_addr > *mac); > +int mac_to_ipv6(const struct ether_addr *mac, alfred_addr *addr); > +int ipv6_to_mac(const alfred_addr *addr, struct ether_addr *mac); > +int ipv4_to_mac(const alfred_addr *addr, struct ether_addr *mac); >  int is_ipv6_eui64(const struct in6_addr *addr); >   >  #endif > diff --git a/client.c b/client.c > index 357fdb9..4102046 100644 > --- a/client.c > +++ b/client.c > @@ -239,7 +239,7 @@ static int check_interface(const char *iface) >   return -1; >   } >   > - sock = socket(PF_INET6, SOCK_DGRAM, 0); > + sock = socket(PF_INET, SOCK_DGRAM, 0); >   if (sock < 0) { >   perror("can't open socket"); >   return -1; > diff --git a/main.c b/main.c > index 0d30ea4..446eecf 100644 > --- a/main.c > +++ b/main.c > @@ -19,6 +19,7 @@ >   * >   */ >   > +#include <arpa/inet.h> >  #include <getopt.h> >  #include <signal.h> >  #include <stdio.h> > @@ -61,6 +62,7 @@ static void alfred_usage(void) >   printf("                                      other > masters\n"); >   printf("  -p, --sync-period [period]          set > synchronization period, in seconds\n"); >   printf("                                      fractional > seconds are supported (i.e. 0.2 = 5 Hz)\n"); > + printf("  -4 [group-address]                  specify IPv4 > multicast address and operate in IPv4 mode"); >   printf("\n"); >   printf("  -u, --unix-path [path]              path to unix > socket used for client-server\n"); >   printf("                                      communication > (default: ""ALFRED_SOCK_PATH_DEFAULT"")\n"); > @@ -196,6 +198,7 @@ static struct globals *alfred_init(int argc, char > *argv[]) >   globals->mesh_iface = "bat0"; >   globals->unix_path = ALFRED_SOCK_PATH_DEFAULT; >   globals->verbose = 0; > + globals->ipv4mode = 0; >   globals->update_command = NULL; >   globals->sync_period.tv_sec = ALFRED_INTERVAL; >   globals->sync_period.tv_nsec = 0; > @@ -204,7 +207,7 @@ static struct globals *alfred_init(int argc, char > *argv[]) >   >   time_random_seed(); >   > - while ((opt = getopt_long(argc, argv, > "ms:r:hi:b:vV:M:I:u:dc:p:", long_options, > + while ((opt = getopt_long(argc, argv, > "ms:r:hi:b:vV:M:I:u:dc:p:4:", long_options, >     &opt_ind)) != -1) { >   switch (opt) { >   case 'r': > @@ -273,10 +276,15 @@ static struct globals *alfred_init(int argc, > char *argv[]) >   return NULL; >   case 'p': >   sync_period = strtod(optarg, NULL); > - globals->sync_period.tv_sec = (int) > sync_period; > - globals->sync_period.tv_nsec = (double) > (sync_period - (int) sync_period) * 1e9; > + globals->sync_period.tv_sec = > (int)sync_period; > + globals->sync_period.tv_nsec = > (double)(sync_period - (int)sync_period) * 1e9; >   printf(" ** Setting sync interval to: %.9f > seconds (%ld.%09ld)\n", sync_period, globals->sync_period.tv_sec, > globals->sync_period.tv_nsec); >   break; > + case '4': > + globals->ipv4mode = 1; > + inet_pton(AF_INET, optarg, > &alfred_mcast.ipv4); > + printf(" ** IPv4 Multicast Mode: %x\n", > alfred_mcast.ipv4.s_addr); > + break; >   case 'h': >   default: >   alfred_usage(); > diff --git a/man/alfred.8 b/man/alfred.8 > index 5936e64..a2c3d4c 100644 > --- a/man/alfred.8 > +++ b/man/alfred.8 > @@ -123,6 +123,11 @@ as arguments. >  Specify alfred synchronization period, in seconds. If not specified, > the default >  ALFRED_INTERVAL setting of 10 seconds will be used. Fractional > seconds are >  supported. > +.TP > +\fB-4 \fIgroup-address\fP \fP > +Specify the IPv4 multicast group address and enable IPv4 data- > sharing (disabling > +IPv6 communication). This option is required on systems that do not > support IPv6 > +addressing. >  . >  .SH EXAMPLES >  Start an alfred server listening on bridge br0 (assuming that this > bridge > diff --git a/netsock.c b/netsock.c > index 86db8a6..0df7701 100644 > --- a/netsock.c > +++ b/netsock.c > @@ -43,10 +43,12 @@ >  #include "list.h" >  #include "hash.h" >   > -const struct in6_addr in6addr_localmcast = {{{ 0xff, 0x02, 0x00, > 0x00, > -        0x00, 0x00, 0x00, > 0x00, > -        0x00, 0x00, 0x00, > 0x00, > -        0x00, 0x00, 0x00, > 0x01 } } }; > +alfred_addr alfred_mcast = { > + .ipv6 = {{{ 0xff, 0x02, 0x00, 0x00, > +     0x00, 0x00, 0x00, 0x00, > +     0x00, 0x00, 0x00, 0x00, > +     0x00, 0x00, 0x00, 0x01 } } } > +}; >   >  static int server_compare(void *d1, void *d2) >  { > @@ -262,7 +264,7 @@ static int netsock_open(struct interface > *interface) >   memset(&sin6_mc, 0, sizeof(sin6_mc)); >   sin6_mc.sin6_port = htons(ALFRED_PORT); >   sin6_mc.sin6_family = AF_INET6; > - memcpy(&sin6_mc.sin6_addr, &in6addr_localmcast, > + memcpy(&sin6_mc.sin6_addr, &alfred_mcast, >          sizeof(sin6_mc.sin6_addr)); >   sin6_mc.sin6_scope_id = interface->scope_id; >   > @@ -291,7 +293,7 @@ static int netsock_open(struct interface > *interface) >   goto err; >   } >   > - memcpy(&mreq.ipv6mr_multiaddr, &in6addr_localmcast, > + memcpy(&mreq.ipv6mr_multiaddr, &alfred_mcast, >          sizeof(mreq.ipv6mr_multiaddr)); >   mreq.ipv6mr_interface = interface->scope_id; >   > @@ -335,6 +337,132 @@ err: >   return -1; >  } >   > +static int netsock_open4(struct interface *interface) > +{ > + int sock; > + int sock_mc; > + struct sockaddr_in sin4, sin_mc; > + struct ip_mreq mreq; > + struct ifreq ifr; > + int ret; > + > + interface->netsock = -1; > + interface->netsock_mcast = -1; > + > + sock = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); > + if (sock  < 0) { > + perror("ipv4: can't open socket"); > + return -1; > + } > + > + sock_mc = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP); > + if (sock_mc  < 0) { > + perror("ipv4: can't open mc socket"); > + return -1; > + } > + > + memset(&ifr, 0, sizeof(ifr)); > + strncpy(ifr.ifr_name, interface->interface, IFNAMSIZ); > + ifr.ifr_name[IFNAMSIZ - 1] = '\0'; > + if (ioctl(sock_mc, SIOCGIFHWADDR, &ifr) == -1) { > + perror("ipv4: can't get MAC address"); > + goto err; > + } > + memcpy(&interface->hwaddr, &ifr.ifr_hwaddr.sa_data, 6); > + > + memset(&sin4, 0, sizeof(sin4)); > + sin4.sin_port = htons(ALFRED_PORT); > + sin4.sin_family = AF_INET; > + sin4.sin_addr.s_addr = INADDR_ANY; > + > + memset(&sin_mc, 0, sizeof(sin_mc)); > + sin_mc.sin_port = htons(ALFRED_PORT); > + sin_mc.sin_family = AF_INET; > + memcpy(&sin_mc.sin_addr, &alfred_mcast, > sizeof(sin_mc.sin_addr)); > + > + enable_raw_bind_capability(1); > + if (setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE, interface- > >interface, > +        strlen(interface->interface) + 1)) { > + perror("ipv4: can't bind to device"); > + goto err; > + } > + > + if (setsockopt(sock_mc, SOL_SOCKET, SO_BINDTODEVICE, > +        interface->interface, strlen(interface- > >interface) + 1)) { > + perror("ipv4: can't bind to device"); > + goto err; > + } > + enable_raw_bind_capability(0); > + > + ret = 1; > + if (setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &ret, > sizeof(ret)) < 0) { > + perror("ipv4: can't set reuse flag"); > + goto err; > + } > + if (setsockopt(sock_mc, SOL_SOCKET, SO_REUSEADDR, &ret, > sizeof(ret)) < 0) { > + perror("ipv4: can't set mc reuse flag"); > + goto err; > + } > + > + if (bind(sock, (struct sockaddr *)&sin4, sizeof(sin4)) < 0) > { > + perror("ipv4: can't bind"); > + goto err; > + } > + > + if (bind(sock_mc, (struct sockaddr *)&sin_mc, > sizeof(sin_mc)) < 0) { > + perror("ipv4: can't bind mc"); > + goto err; > + } > + > + memcpy(&mreq.imr_multiaddr, &alfred_mcast.ipv4, > sizeof(mreq.imr_multiaddr)); > + > + if (ioctl(sock_mc, SIOCGIFADDR, &ifr) < 0) { > + perror("ipv4: can't get IP address"); > + goto err; > + } > + mreq.imr_interface = ((struct sockaddr_in *)&ifr.ifr_addr)- > >sin_addr; > + memcpy(&interface->address.ipv4, > +        &((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr, > +        sizeof(struct in_addr)); > + > + if (setsockopt(sock_mc, IPPROTO_IP, IP_ADD_MEMBERSHIP, > &mreq, sizeof(mreq))) { > + perror("ipv4: can't add multicast membership"); > + goto err; > + } > + > + ret = fcntl(sock, F_GETFL, 0); > + if (ret < 0) { > + perror("failed to get file status flags"); > + goto err; > + } > + > + ret = fcntl(sock, F_SETFL, ret | O_NONBLOCK); > + if (ret < 0) { > + perror("failed to set file status flags"); > + goto err; > + } > + > + ret = fcntl(sock_mc, F_GETFL, 0); > + if (ret < 0) { > + perror("ipv4: failed to get file status flags"); > + goto err; > + } > + > + ret = fcntl(sock_mc, F_SETFL, ret | O_NONBLOCK); > + if (ret < 0) { > + perror("ipv4: failed to set file status flags"); > + goto err; > + } > + > + interface->netsock = sock; > + interface->netsock_mcast = sock_mc; > + > + return 0; > +r: > + close(sock_mc); > + return -1; > +} > + >  int netsock_open_all(struct globals *globals) >  { >   int num_socks = 0; > @@ -342,7 +470,11 @@ int netsock_open_all(struct globals *globals) >   struct interface *interface; >   >   list_for_each_entry(interface, &globals->interfaces, list) { > - ret = netsock_open(interface); > + if (globals->ipv4mode) > + ret = netsock_open4(interface); > + else > + ret = netsock_open(interface); > + >   if (ret >= 0) >   num_socks++; >   } > @@ -355,8 +487,12 @@ void netsock_reopen(struct globals *globals) >   struct interface *interface; >   >   list_for_each_entry(interface, &globals->interfaces, list) { > - if (interface->netsock < 0) > - netsock_open(interface); > + if (interface->netsock < 0) { > + if (globals->ipv4mode) > + netsock_open4(interface); > + else > + netsock_open(interface); > + } >   } >  } >   > @@ -430,7 +566,7 @@ int netsock_receive_packet(struct globals > *globals, fd_set *fds) >  } >   >  int netsock_own_address(const struct globals *globals, > - const struct in6_addr *address) > + const alfred_addr *address) >  { >   struct interface *interface; >   > diff --git a/recv.c b/recv.c > index bb8cc05..39df07f 100644 > --- a/recv.c > +++ b/recv.c > @@ -190,7 +190,7 @@ static int finish_alfred_transaction(struct > globals *globals, >  } >   >  static int process_alfred_push_data(struct globals *globals, > -     struct in6_addr *source, > +     alfred_addr *source, >       struct alfred_push_data_v0 > *push) >  { >   int len; > @@ -200,7 +200,10 @@ static int process_alfred_push_data(struct > globals *globals, >   struct transaction_packet *transaction_packet; >   int found; >   > - ret = ipv6_to_mac(source, &mac); > + if (globals->ipv4mode) > + ret = ipv4_to_mac(source, &mac); > + else > + ret = ipv6_to_mac(source, &mac); >   if (ret < 0) >   goto err; >   > @@ -260,7 +263,7 @@ err: >  static int >  process_alfred_announce_master(struct globals *globals, >          struct interface *interface, > -        struct in6_addr *source, > +        alfred_addr *source, >          struct alfred_announce_master_v0 > *announce) >  { >   struct server *server; > @@ -271,7 +274,10 @@ process_alfred_announce_master(struct globals > *globals, >   >   len = ntohs(announce->header.length); >   > - ret = ipv6_to_mac(source, &mac); > + if (globals->ipv4mode) > + ret = ipv4_to_mac(source, &mac); > + else > + ret = ipv6_to_mac(source, &mac); >   if (ret < 0) >   return -1; >   > @@ -316,7 +322,7 @@ process_alfred_announce_master(struct globals > *globals, >   >  static int process_alfred_request(struct globals *globals, >     struct interface *interface, > -   struct in6_addr *source, > +   alfred_addr *source, >     struct alfred_request_v0 *request) >  { >   int len; > @@ -336,7 +342,7 @@ static int process_alfred_request(struct globals > *globals, >  } >   >  static int process_alfred_status_txend(struct globals *globals, > -        struct in6_addr *source, > +        alfred_addr *source, >          struct alfred_status_v0 > *request) >  { >   struct transaction_head search, *head; > @@ -351,7 +357,10 @@ static int process_alfred_status_txend(struct > globals *globals, >   if (len != (sizeof(*request) - sizeof(request->header))) >   return -1; >   > - ret = ipv6_to_mac(source, &mac); > + if (globals->ipv4mode) > + ret = ipv4_to_mac(source, &mac); > + else > + ret = ipv6_to_mac(source, &mac); >   if (ret < 0) >   return -1; >   > @@ -389,15 +398,25 @@ int recv_alfred_packet(struct globals *globals, > struct interface *interface, >   uint8_t buf[MAX_PAYLOAD]; >   ssize_t length; >   struct alfred_tlv *packet; > - struct sockaddr_in6 source; > + struct sockaddr_in *source; > + struct sockaddr_in source4; > + struct sockaddr_in6 source6; >   socklen_t sourcelen; > + alfred_addr alfred_source; >   >   if (interface->netsock < 0) >   return -1; >   > - sourcelen = sizeof(source); > + if (globals->ipv4mode) { > + source = (struct sockaddr_in *)&source4; > + sourcelen = sizeof(source4); > + } else { > + source = (struct sockaddr_in *)&source6; > + sourcelen = sizeof(source6); > + } > + >   length = recvfrom(recv_sock, buf, sizeof(buf), 0, > -   (struct sockaddr *)&source, &sourcelen); > +   (struct sockaddr *)source, &sourcelen); >   if (length <= 0) { >   perror("read from network socket failed"); >   return -1; > @@ -405,12 +424,18 @@ int recv_alfred_packet(struct globals *globals, > struct interface *interface, >   >   packet = (struct alfred_tlv *)buf; >   > - /* drop packets not sent over link-local ipv6 */ > - if (!is_ipv6_eui64(&source.sin6_addr)) > - return -1; > + if (globals->ipv4mode) { > + memcpy(&alfred_source, &source4.sin_addr, > sizeof(source4.sin_addr)); > + } else { > + memcpy(&alfred_source, &source6.sin6_addr, > sizeof(source6.sin6_addr)); > + > + /* drop packets not sent over link-local ipv6 */ > + if (!is_ipv6_eui64(&alfred_source.ipv6)) > + return -1; > + } >   >   /* drop packets from ourselves */ > - if (netsock_own_address(globals, &source.sin6_addr)) > + if (netsock_own_address(globals, &alfred_source)) >   return -1; >   >   /* drop truncated packets */ > @@ -424,20 +449,20 @@ int recv_alfred_packet(struct globals *globals, > struct interface *interface, >   >   switch (packet->type) { >   case ALFRED_PUSH_DATA: > - process_alfred_push_data(globals, &source.sin6_addr, > + process_alfred_push_data(globals, &alfred_source, >    (struct alfred_push_data_v0 > *)packet); >   break; >   case ALFRED_ANNOUNCE_MASTER: >   process_alfred_announce_master(globals, interface, > -        &source.sin6_addr, > +        &alfred_source, >          (struct > alfred_announce_master_v0 *)packet); >   break; >   case ALFRED_REQUEST: > - process_alfred_request(globals, interface, > &source.sin6_addr, > + process_alfred_request(globals, interface, > &alfred_source, >          (struct alfred_request_v0 > *)packet); >   break; >   case ALFRED_STATUS_TXEND: > - process_alfred_status_txend(globals, > &source.sin6_addr, > + process_alfred_status_txend(globals, &alfred_source, >       (struct alfred_status_v0 > *)packet); >   break; >   default: > diff --git a/send.c b/send.c > index c7a2af2..b566503 100644 > --- a/send.c > +++ b/send.c > @@ -42,7 +42,7 @@ int announce_master(struct globals *globals) >   announcement.header.version = ALFRED_VERSION; >   announcement.header.length = htons(0); >   > - send_alfred_packet(interface, &in6addr_localmcast, > + send_alfred_packet(globals, interface, > &alfred_mcast, >      &announcement, > sizeof(announcement)); >   } >   > @@ -50,7 +50,7 @@ int announce_master(struct globals *globals) >  } >   >  int push_data(struct globals *globals, struct interface *interface, > -       struct in6_addr *destination, enum data_source > max_source_level, > +       alfred_addr *destination, enum data_source > max_source_level, >         int type_filter, uint16_t tx_id) >  { >   struct hash_it_t *hashit = NULL; > @@ -90,7 +90,7 @@ int push_data(struct globals *globals, struct > interface *interface, >   tlv_length += sizeof(*push) - sizeof(push- > >header); >   push->header.length = htons(tlv_length); >   push->tx.seqno = htons(seqno++); > - send_alfred_packet(interface, destination, > push, > + send_alfred_packet(globals, interface, > destination, push, >      sizeof(*push) + > total_length); >   total_length = 0; >   } > @@ -114,7 +114,7 @@ int push_data(struct globals *globals, struct > interface *interface, >   tlv_length += sizeof(*push) - sizeof(push->header); >   push->header.length = htons(tlv_length); >   push->tx.seqno = htons(seqno++); > - send_alfred_packet(interface, destination, push, > + send_alfred_packet(globals, interface, destination, > push, >      sizeof(*push) + total_length); >   } >   > @@ -128,7 +128,7 @@ int push_data(struct globals *globals, struct > interface *interface, >   status_end.tx.id = tx_id; >   status_end.tx.seqno = htons(seqno); >   > - send_alfred_packet(interface, destination, > &status_end, > + send_alfred_packet(globals, interface, destination, > &status_end, >      sizeof(status_end)); >   } >   > @@ -170,24 +170,38 @@ int push_local_data(struct globals *globals) >   return 0; >  } >   > -ssize_t send_alfred_packet(struct interface *interface, > -    const struct in6_addr *dest, void *buf, > int length) > +ssize_t send_alfred_packet(struct globals *globals, struct interface > *interface, > +    const alfred_addr *dest, void *buf, int > length) >  { >   ssize_t ret; > - struct sockaddr_in6 dest_addr; > - > - memset(&dest_addr, 0, sizeof(dest_addr)); > - dest_addr.sin6_family = AF_INET6; > - dest_addr.sin6_port = htons(ALFRED_PORT); > - dest_addr.sin6_scope_id = interface->scope_id; > - memcpy(&dest_addr.sin6_addr, dest, sizeof(*dest)); > + struct sockaddr *dest_addr; > + struct sockaddr_in6 dest_addr6; > + struct sockaddr_in dest_addr4; > + socklen_t slen; > + > + if (globals->ipv4mode) { > + memset(&dest_addr4, 0, sizeof(dest_addr4)); > + dest_addr4.sin_family = AF_INET; > + dest_addr4.sin_port = htons(ALFRED_PORT); > + memcpy(&dest_addr4.sin_addr, &dest->ipv4, > sizeof(dest->ipv4)); > + > + slen = sizeof(struct sockaddr_in); > + dest_addr = (struct sockaddr *)&dest_addr4; > + } else { > + memset(&dest_addr6, 0, sizeof(dest_addr6)); > + dest_addr6.sin6_family = AF_INET6; > + dest_addr6.sin6_port = htons(ALFRED_PORT); > + dest_addr6.sin6_scope_id = interface->scope_id; > + memcpy(&dest_addr6.sin6_addr, &dest->ipv6, > sizeof(dest->ipv6)); > + > + slen = sizeof(struct sockaddr_in6); > + dest_addr = (struct sockaddr *)&dest_addr6; > + } >   >   if (interface->netsock < 0) >   return 0; >   > - ret = sendto(interface->netsock, buf, length, 0, > -      (struct sockaddr *)&dest_addr, > -      sizeof(struct sockaddr_in6)); > + ret = sendto(interface->netsock, buf, length, 0, dest_addr, > slen); >   if (ret == -EPERM) { >   perror("Error during sent"); >   close(interface->netsock); > diff --git a/server.c b/server.c > index f6e0c8a..2c4042a 100644 > --- a/server.c > +++ b/server.c > @@ -218,7 +218,7 @@ static int purge_data(struct globals *globals) >   return 0; >  } >   > -static void check_if_socket(struct interface *interface) > +static void check_if_socket(struct interface *interface, struct > globals *globals) >  { >   int sock; >   struct ifreq ifr; > @@ -226,7 +226,7 @@ static void check_if_socket(struct interface > *interface) >   if (interface->netsock < 0) >   return; >   > - sock = socket(PF_INET6, SOCK_DGRAM, 0); > + sock = socket(PF_INET, SOCK_DGRAM, 0); >   if (sock < 0) { >   perror("can't open socket"); >   return; > @@ -240,7 +240,7 @@ static void check_if_socket(struct interface > *interface) >   goto close; >   } >   > - if (interface->scope_id != (uint32_t)ifr.ifr_ifindex) { > + if (!globals->ipv4mode && (interface->scope_id != > (uint32_t)ifr.ifr_ifindex)) { >   fprintf(stderr, >   "iface index changed from %"PRIu32" to %d, > closing netsock\n", >   interface->scope_id, ifr.ifr_ifindex); > @@ -282,7 +282,7 @@ static void check_if_sockets(struct globals > *globals) >   globals->if_check = now; >   >   list_for_each_entry(interface, &globals->interfaces, list) > - check_if_socket(interface); > + check_if_socket(interface, globals); >  } >   >  static void execute_update_command(struct globals *globals) > diff --git a/unix_sock.c b/unix_sock.c > index 0a819a2..4a8c6e0 100644 > --- a/unix_sock.c > +++ b/unix_sock.c > @@ -258,7 +258,7 @@ static int unix_sock_req_data(struct globals > *globals, >   head->client_socket = client_sock; >   head->requested_type = request->requested_type; >   > - send_alfred_packet(interface, &globals->best_server- > >address, > + send_alfred_packet(globals, interface, &globals- > >best_server->address, >      request, sizeof(*request)); >   >   return 0;