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Fix broadcast address check

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This commit is contained in:
Alex Forencich 2021-08-08 13:25:39 -07:00
parent 52d8867f73
commit 81673727a4
1 changed files with 15 additions and 7 deletions
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22
rtl/arp.v
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@ -382,18 +382,26 @@ always @* begin
end
end
end else if (arp_request_valid && arp_request_ready) begin
if (~(arp_request_ip | subnet_mask) == 0) begin
// broadcast address
// (all bits in request IP set where subnet mask is clear)
if (arp_request_ip == 32'hffffffff) begin
// broadcast address; use broadcast MAC address
arp_response_valid_next = 1'b1;
arp_response_error_next = 1'b0;
arp_response_mac_next = 48'hffffffffffff;
end else if (((arp_request_ip ^ gateway_ip) & subnet_mask) == 0) begin
// within subnet, look up IP directly
// within subnet
// (no bits differ between request IP and gateway IP where subnet mask is set)
cache_query_request_valid_next = 1'b1;
cache_query_request_ip_next = arp_request_ip;
arp_request_ip_next = arp_request_ip;
if (~(arp_request_ip | subnet_mask) == 0) begin
// broadcast address; use broadcast MAC address
// (all bits in request IP set where subnet mask is clear)
arp_response_valid_next = 1'b1;
arp_response_error_next = 1'b0;
arp_response_mac_next = 48'hffffffffffff;
end else begin
// unicast address; look up IP directly
cache_query_request_valid_next = 1'b1;
cache_query_request_ip_next = arp_request_ip;
arp_request_ip_next = arp_request_ip;
end
end else begin
// outside of subnet, so look up gateway address
cache_query_request_valid_next = 1'b1;