ARP ARP 8/ INF5060: Multimedia data communication using network processors

2004 Carsten Griwodz & Pål HalvorsenINF5060 – multimedia communication using network processors Assignment 5  Extend the simple packet bridge from assignment 4 with ARP support  build an ARP table to dynamically bind/map an IP address to a mac address and an interface on the card  check IP address and forward packet to correct interface  be aware of broadcast loops

2004 Carsten Griwodz & Pål HalvorsenINF5060 – multimedia communication using network processors ARP Packet MAC src MAC dest MAS src type Hardware type = 1Protocol type = 0x800 MACaddr len=6Netaddr len=4Opcode Sender MAC address Sender IP address Receiver MAC address Receiver IP address … only for readability … Opcode: Request:1 Reply:2 Sender MAC address: mandatory Sender IP address: mandatory Receiver MAC address Request: 0 Reply: requester’s MAC address Receiver IP address: mandatory

2004 Carsten Griwodz & Pål HalvorsenINF5060 – multimedia communication using network processors Broadcast problem IXP1200

2004 Carsten Griwodz & Pål HalvorsenINF5060 – multimedia communication using network processors ARP caching  Most OSes do ARP caching  Our bridge does it for building and maintained a spanning tree  Two proposed caches  Address-to-interface mapping  Broadcast suppression Last refresh cycle count (64 bit)IP address (32 bit)IF (32 bit)Last seen cycle count (64 bit)IP source (32 bit) MAC dest (48 bit) MAC source (48 bit) xbuf_alloc [$cyclect,2] csr[read, $cyclect[0], CYCLE_CNT] xbuf_free[$cyclect] Microengine clock speed: 232 Mhz

2004 Carsten Griwodz & Pål HalvorsenINF5060 – multimedia communication using network processors Allocating cache memory  Memory must be allocated by StrongARM  Memory offset must be passed to microengines in shared memory  E.g. e = RmMalloc(RM_SRAM, &ptr, n*4); space for n address-to-IF mapping entries e = RmGetPhysOffset(RM_SRAM, ptr, &sram_offset); e = RmMalloc(RM_SCRATCH, &ptrptr, 1); space for pointer to cache e = RmGetPhysOffset(RM_SCRATCH, ptrptr, &sramptr_offset); e = RmWrite(RM_SCRATCH, sramptr_offset, sram_offset, 0); for( i=0; i<6; i++ ) { sym.meNumber = i; bzero(sym.name, MAX_SIZE_OF_IMPORTED_SYMBOL); strncpy(sym.name, CACHE_PTR_STR, MAX_SIZE_OF_IMPORTED_SYMBOL); sym.value = sramptr_offset; e = RmUencPatchSymbol(i,&sym,1); }