Handle hello packets
This commit is contained in:
parent
c5a1d00fc4
commit
afffa65f90
3 changed files with 133 additions and 12 deletions
136
ffd/ffd.c
136
ffd/ffd.c
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@ -52,7 +52,6 @@ static const eth_addr_t ffd_addr = {{0x03, 0x00, 0x00, 0x00, 0x0f, 0xfd}};
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static char *mesh = "bat0";
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static unsigned mtu = 1528;
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static int sockfd;
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static struct timespec now;
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@ -114,6 +113,16 @@ static bool init_socket() {
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return true;
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}
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static inline ffd_iface_t* get_iface(unsigned ifindex) {
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ffd_iface_t *iface;
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for (iface = iface_list; iface; iface = iface->next) {
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if (iface->ifindex == ifindex)
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return iface;
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}
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return NULL;
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}
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static void update_netif(const char *ifname, unsigned ifindex, void *arg) {
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if (!use_netif(ifname))
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return;
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@ -128,11 +137,7 @@ static void update_netif(const char *ifname, unsigned ifindex, void *arg) {
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if (setsockopt(sockfd, SOL_PACKET, PACKET_ADD_MEMBERSHIP, &mr, sizeof(mr)) && errno != EADDRINUSE)
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fprintf(stderr, "warning: setsockopt: %m\n");
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ffd_iface_t *iface;
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for (iface = iface_list; iface; iface = iface->next) {
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if (iface->ifindex == ifindex)
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break;
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}
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ffd_iface_t *iface = get_iface(ifindex);
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if (!iface) {
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/* new iface */
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@ -141,7 +146,7 @@ static void update_netif(const char *ifname, unsigned ifindex, void *arg) {
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iface_list = iface;
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iface->seqno = 0;
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iface->neighs = NULL;
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iface->neigh_list = NULL;
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}
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iface->ifindex = ifindex;
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@ -149,6 +154,41 @@ static void update_netif(const char *ifname, unsigned ifindex, void *arg) {
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iface->type = netif_get_type(ifname);
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}
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static inline ffd_neigh_t* get_neigh(const ffd_iface_t *iface, const eth_addr_t *addr) {
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ffd_neigh_t *neigh;
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for (neigh = iface->neigh_list; neigh; neigh = neigh->next) {
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if (are_eth_addrs_equal(addr, &neigh->addr))
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return neigh;
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}
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return neigh;
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}
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static ffd_neigh_t* get_neigh_create(ffd_iface_t *iface, const eth_addr_t *addr) {
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ffd_neigh_t *neigh = get_neigh(iface, addr);
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if (!neigh) {
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neigh = malloc(sizeof(ffd_neigh_t));
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neigh->next = iface->neigh_list;
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iface->neigh_list = neigh;
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neigh->addr = *addr;
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neigh->hello_log = 0;
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neigh->hello_interval = 0;
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neigh->last_seqno = 0;
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neigh->last_hello = (struct timespec){};
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}
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return neigh;
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}
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static void free_neighs(ffd_neigh_t *neigh) {
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ffd_neigh_t *next;
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for (; neigh; neigh = next) {
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next = neigh->next;
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free(neigh);
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}
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}
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static void update_netifs() {
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ffd_iface_t *iface, **cur;
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@ -163,6 +203,8 @@ static void update_netifs() {
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if (iface->type == IF_UNSPEC) {
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*cur = iface->next;
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free_neighs(iface->neigh_list);
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free(iface);
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}
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else {
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@ -226,19 +268,93 @@ static void send_hellos() {
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}
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}
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static void handle_tlv_hello(const ffd_tlv_hello_t *tlv_hello, size_t len, const eth_addr_t *addr, ffd_iface_t *iface) {
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if (len < sizeof(ffd_tlv_hello_t)) {
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fprintf(stderr, "warn: received short hello TLV.\n");
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return;
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}
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fprintf(stderr, "debug: received hello with seqno %u.\n", ntohs(tlv_hello->seqno));
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ffd_neigh_t *neigh = get_neigh_create(iface, addr);
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uint16_t seqno = ntohs(tlv_hello->seqno);
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if (neigh->last_hello.tv_sec) {
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int16_t seqdiff = seqno - neigh->last_seqno;
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if (seqdiff <= 0) {
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fprintf(stderr, "debug: seqno already seen, ignorin.\n");
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return;
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}
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int timediff = timespec_diff(&now, &neigh->last_hello)/10;
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uint16_t seqexp = neigh->last_seqno + (timediff - neigh->hello_interval/2)/neigh->hello_interval;
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/* cast to int16_t to ensure correct handling of seqno wrapping */
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if (abs((int16_t)(seqno - seqexp)) > 16) {
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fprintf(stderr, "info: neighbor was reset.\n");
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neigh->hello_log = 0;
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}
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else {
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neigh->hello_log <<= seqdiff;
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}
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}
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else {
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fprintf(stderr, "info: received hello from new neighbor.\n");
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}
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neigh->hello_log |= 1;
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neigh->hello_interval = ntohs(tlv_hello->interval);
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neigh->last_seqno = seqno;
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neigh->last_hello = now;
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fprintf(stderr, "debug: accepted hello, log %04x.\n", neigh->hello_log);
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}
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static void handle_tlv(ffd_tlv_type_t type, const void *data, size_t len, void *arg) {
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const struct sockaddr_ll *from = arg;
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const eth_addr_t *addr = (const eth_addr_t*)from->sll_addr;
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ffd_iface_t *iface = get_iface(from->sll_ifindex);
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if (!iface)
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return;
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switch (type) {
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case TLV_HELLO:
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handle_tlv_hello(data, len, addr, iface);
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return;
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default:
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fprintf(stderr, "debug: received unknown TLV %u on %s.\n", type, iface->name);
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return;
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}
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}
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static void receive_packet() {
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uint8_t buf[mtu];
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ffd_packet_t *packet = alloca(sizeof(ffd_packet_t)+PACKET_MAX);
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struct sockaddr_ll from;
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socklen_t fromlen = sizeof(from);
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ssize_t readlen = recvfrom(sockfd, buf, sizeof(buf), 0, (struct sockaddr*)&from, &fromlen);
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ssize_t readlen = recvfrom(sockfd, packet, sizeof(ffd_packet_t)+PACKET_MAX, 0, (struct sockaddr*)&from, &fromlen);
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if (readlen < 0) {
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fprintf(stderr, "error: recvfrom: %m\n");
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return;
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}
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fprintf(stderr, "debug: read %zi bytes.\n", readlen);
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if (from.sll_halen != ETH_ALEN) {
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fprintf(stderr, "error: receive_packet: strange address length\n");
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return;
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}
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if (readlen < sizeof(ffd_packet_t) || readlen < sizeof(ffd_packet_t)+ntohs(packet->len)) {
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fprintf(stderr, "debug: received short packet.\n");
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return;
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}
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if (!ffd_tlv_parse(packet, handle_tlv, &from)) {
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fprintf(stderr, "debug: received invalid packet.\n");
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}
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}
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int main() {
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@ -45,6 +45,11 @@ typedef struct _ffd_neigh_t {
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struct _ffd_neigh_t *next;
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eth_addr_t addr;
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uint16_t hello_log;
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uint16_t hello_interval;
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uint16_t last_seqno;
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struct timespec last_hello;
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} ffd_neigh_t;
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typedef struct _ffd_iface_t {
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@ -56,7 +61,7 @@ typedef struct _ffd_iface_t {
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netif_type_t type;
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uint16_t seqno;
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ffd_neigh_t *neighs;
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ffd_neigh_t *neigh_list;
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} ffd_iface_t;
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#endif /* _FFD_FFD_H_ */
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@ -36,7 +36,7 @@ bool ffd_tlv_parse(const ffd_packet_t *packet, ffd_tlv_cb cb, void *arg) {
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if (packet->version_magic != htons(FFD_VERSION_MAGIC))
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return false;
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const uint8_t *data = packet->tlv + 2, *end = packet->tlv + packet->len;
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const uint8_t *data = packet->tlv + 2, *end = packet->tlv + ntohs(packet->len);
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while (data <= end) {
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if (data[-2] == TLV_PAD1) {
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