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rdc: duplicate packets: Keep only the last sequence number for each address
According to IEEE 802.15.4e (§6.4.3.9), in order to detect duplicate received MAC-layer frames, only the most recently received frame's sequence number needs to be stored for each unique device address. Doing so limits the possible false duplicate packet detections to a single sequence number. This also allows to keep the last sequence number of more device addresses for the same value of MAX_SEQNOS. Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
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@ -72,12 +72,14 @@ mac_sequence_is_duplicate(void)
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* packet with the last few ones we saw.
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*/
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for(i = 0; i < MAX_SEQNOS; ++i) {
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if(packetbuf_attr(PACKETBUF_ATTR_PACKET_ID) == received_seqnos[i].seqno &&
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rimeaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_SENDER),
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if(rimeaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_SENDER),
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&received_seqnos[i].sender)) {
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if(packetbuf_attr(PACKETBUF_ATTR_PACKET_ID) == received_seqnos[i].seqno) {
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/* Duplicate packet. */
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return 1;
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}
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break;
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}
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}
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return 0;
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}
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@ -85,10 +87,20 @@ mac_sequence_is_duplicate(void)
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void
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mac_sequence_register_seqno(void)
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{
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int i;
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int i, j;
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for(i = MAX_SEQNOS - 1; i > 0; --i) {
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memcpy(&received_seqnos[i], &received_seqnos[i - 1], sizeof(struct seqno));
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/* Locate possible previous sequence number for this address. */
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for(i = 0; i < MAX_SEQNOS; ++i) {
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if(rimeaddr_cmp(packetbuf_addr(PACKETBUF_ADDR_SENDER),
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&received_seqnos[i].sender)) {
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i++;
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break;
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}
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}
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/* Keep the last sequence number for each address as per 802.15.4e. */
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for(j = i - 1; j > 0; --j) {
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memcpy(&received_seqnos[j], &received_seqnos[j - 1], sizeof(struct seqno));
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}
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received_seqnos[0].seqno = packetbuf_attr(PACKETBUF_ATTR_PACKET_ID);
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rimeaddr_copy(&received_seqnos[0].sender,
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