X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Modules%2FIPStack%2Fipv4.c;h=d16cc97d0d6154a4c21e1320fde27de6a85d3050;hb=2c3ab58b961dea91fdfbf432a7fdf9593c6e7a8e;hp=9723d8d7fb8f4efb040e8b0d5ba9a8c8347db743;hpb=04b368645c34cc3853fc13f93e33ac7878be8479;p=tpg%2Facess2.git diff --git a/Modules/IPStack/ipv4.c b/Modules/IPStack/ipv4.c index 9723d8d7..d16cc97d 100644 --- a/Modules/IPStack/ipv4.c +++ b/Modules/IPStack/ipv4.c @@ -5,29 +5,114 @@ #include "ipstack.h" #include "link.h" #include "ipv4.h" +#include "firewall.h" + +#define DEFAULT_TTL 32 // === IMPORTS === extern tInterface *gIP_Interfaces; +extern void ICMP_Initialise(); +extern int ICMP_Ping(tInterface *Interface, tIPv4 Addr); +extern tMacAddr ARP_Resolve4(tInterface *Interface, tIPv4 Address); // === PROTOTYPES === int IPv4_Initialise(); + int IPv4_RegisterCallback(int ID, tIPCallback Callback); void IPv4_int_GetPacket(tAdapter *Interface, tMacAddr From, int Length, void *Buffer); tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast); Uint32 IPv4_Netmask(int FixedBits); +Uint16 IPv4_Checksum(const void *Buf, size_t Length); + int IPv4_Ping(tInterface *Iface, tIPv4 Addr); // === GLOBALS === tIPCallback gaIPv4_Callbacks[256]; // === CODE === /** - * \fn int IPv4_Initialise() + * \brief Initialise the IPv4 Code */ int IPv4_Initialise() { + ICMP_Initialise(); Link_RegisterType(IPV4_ETHERNET_ID, IPv4_int_GetPacket); return 1; } +/** + * \brief Registers a callback + * \param ID 8-bit packet type ID + * \param Callback Callback function + */ +int IPv4_RegisterCallback(int ID, tIPCallback Callback) +{ + if( ID < 0 || ID > 255 ) return 0; + if( gaIPv4_Callbacks[ID] ) return 0; + gaIPv4_Callbacks[ID] = Callback; + return 1; +} + +/** + * \brief Creates and sends an IPv4 Packet + * \param Iface Interface + * \param Address Destination IP + * \param Protocol Protocol ID + * \param ID Some random ID number + * \param Length Data Length + * \param Data Packet Data + * \return Boolean Success + */ +int IPv4_SendPacket(tInterface *Iface, tIPv4 Address, int Protocol, int ID, int Length, const void *Data) +{ + tMacAddr to = ARP_Resolve4(Iface, Address); + int bufSize = sizeof(tIPv4Header) + Length; + char buf[bufSize]; + tIPv4Header *hdr = (void*)buf; + int ret; + + if( MAC_EQU(to, cMAC_ZERO) ) { + // No route to host + Log_Notice("IPv4", "No route to host %i.%i.%i.%i", + Address.B[0], Address.B[1], Address.B[2], Address.B[3]); + return 0; + } + + // OUTPUT Firewall rule go here + ret = IPTables_TestChain("OUTPUT", + 4, (tIPv4*)Iface->Address, &Address, + Protocol, 0, + Length, Data); + if(ret > 0) { + // Just drop it (with an error) + Log_Notice("IPv4", "Firewall dropped packet"); + return 0; + } + + memcpy(&hdr->Options[0], Data, Length); + hdr->Version = 4; + hdr->HeaderLength = sizeof(tIPv4Header)/4; + hdr->DiffServices = 0; // TODO: Check + + hdr->Reserved = 0; + hdr->DontFragment = 0; + hdr->MoreFragments = 0; + hdr->FragOffLow = 0; + hdr->FragOffHi = 0; + + hdr->TotalLength = htons( bufSize ); + hdr->Identifcation = htons( ID ); // TODO: Check + hdr->TTL = DEFAULT_TTL; + hdr->Protocol = Protocol; + hdr->HeaderChecksum = 0; // Will be set later + hdr->Source = *(tIPv4*)Iface->Address; + hdr->Destination = Address; + hdr->HeaderChecksum = htons( IPv4_Checksum(hdr, sizeof(tIPv4Header)) ); + + Log_Log("IPv4", "Sending packet to %i.%i.%i.%i", + Address.B[0], Address.B[1], Address.B[2], Address.B[3]); + Link_SendPacket(Iface->Adapter, IPV4_ETHERNET_ID, to, bufSize, buf); + return 1; +} + /** * \fn void IPv4_int_GetPacket(tInterface *Adapter, tMacAddr From, int Length, void *Buffer) * \brief Process an IPv4 Packet @@ -38,53 +123,167 @@ void IPv4_int_GetPacket(tAdapter *Adapter, tMacAddr From, int Length, void *Buff tInterface *iface; Uint8 *data; int dataLength; + int ret; + if(Length < sizeof(tIPv4Header)) return; + #if 0 + //Log_Log("IPv4", "Version = %i", hdr->Version); + //Log_Log("IPv4", "HeaderLength = %i", hdr->HeaderLength); + //Log_Log("IPv4", "DiffServices = %i", hdr->DiffServices); + Log_Debug("IPv4", "TotalLength = %i", ntohs(hdr->TotalLength) ); + //Log_Log("IPv4", "Identifcation = %i", ntohs(hdr->Identifcation) ); + //Log_Log("IPv4", "TTL = %i", hdr->TTL ); + Log_Debug("IPv4", "Protocol = %i", hdr->Protocol ); + //Log_Log("IPv4", "HeaderChecksum = 0x%x", ntohs(hdr->HeaderChecksum) ); + Log_Debug("IPv4", "Source = %i.%i.%i.%i", + hdr->Source.B[0], hdr->Source.B[1], hdr->Source.B[2], hdr->Source.B[3] ); + Log_Debug("IPv4", "Destination = %i.%i.%i.%i", + hdr->Destination.B[0], hdr->Destination.B[1], + hdr->Destination.B[2], hdr->Destination.B[3] ); + #endif + // Check that the version IS IPv4 - if(hdr->Version != 4) return; + if(hdr->Version != 4) { + Log_Log("IPv4", "hdr->Version(%i) != 4", hdr->Version); + return; + } // Check Header checksum - //TODO + { + Uint16 hdrVal, compVal; + hdrVal = ntohs(hdr->HeaderChecksum); + hdr->HeaderChecksum = 0; + compVal = IPv4_Checksum(hdr, hdr->HeaderLength * 4); + if(hdrVal != compVal) { + Log_Log("IPv4", "Header checksum fails (%04x != %04x)", hdrVal, compVal); + return ; + } + hdr->HeaderChecksum = hdrVal; + } // Check Packet length - if(hdr->TotalLength > Length) return; + if( ntohs(hdr->TotalLength) > Length) { + Log_Log("IPv4", "hdr->TotalLength(%i) > Length(%i)", ntohs(hdr->TotalLength), Length); + return; + } - // Get Interface (allowing broadcasts) - iface = IPv4_GetInterface(Adapter, hdr->Source, 1); - if(!iface) return; // Not for us? Well, let's ignore it + // TODO: Handle packet fragmentation - // Defragment - //TODO - dataLength = hdr->TotalLength - sizeof(tIPv4Header); + // Get Data and Data Length + dataLength = ntohs(hdr->TotalLength) - sizeof(tIPv4Header); data = &hdr->Options[0]; + // Get Interface (allowing broadcasts) + iface = IPv4_GetInterface(Adapter, hdr->Destination, 1); + + // Firewall rules + if( iface ) { + // Incoming Packets + ret = IPTables_TestChain("INPUT", + 4, &hdr->Source, &hdr->Destination, + hdr->Protocol, 0, + dataLength, data + ); + } + else { + // Routed packets + ret = IPTables_TestChain("FORWARD", + 4, &hdr->Source, &hdr->Destination, + hdr->Protocol, 0, + dataLength, data + ); + } + switch(ret) + { + // 0 - Allow + case 0: break; + // 1 - Silent Drop + case 1: + Log_Debug("IPv4", "Silently dropping packet"); + return ; + case -1: + // Bad rule + break ; + // Unknown, silent drop + default: + Log_Warning("IPv4", "Unknown firewall rule"); + return ; + } + + // Routing + if(!iface) + { + tMacAddr to; + tRoute *rt; + + Log_Debug("IPv4", "Route the packet"); + // Drop the packet if the TTL is zero + if( hdr->TTL == 0 ) { + Log_Warning("IPv4", "TODO: Sent ICMP-Timeout when TTL exceeded"); + return ; + } + + hdr->TTL --; + + rt = IPStack_FindRoute(4, NULL, &hdr->Destination); // Get the route (gets the interface) + to = ARP_Resolve4(rt->Interface, hdr->Destination); // Resolve address + if( MAC_EQU(to, cMAC_ZERO) ) + return ; + + // Send packet + Log_Log("IPv4", "Forwarding packet to %i.%i.%i.%i (via %i.%i.%i.%i)", + hdr->Destination.B[0], hdr->Destination.B[1], + hdr->Destination.B[2], hdr->Destination.B[3], + ((tIPv4*)rt->NextHop)->B[0], ((tIPv4*)rt->NextHop)->B[1], + ((tIPv4*)rt->NextHop)->B[2], ((tIPv4*)rt->NextHop)->B[3]); + Link_SendPacket(rt->Interface->Adapter, IPV4_ETHERNET_ID, to, Length, Buffer); + + + return ; + } + // Send it on - gaIPv4_Callbacks[hdr->Protocol] (iface, &hdr->Source, dataLength, data); + if( !gaIPv4_Callbacks[hdr->Protocol] ) { + Log_Log("IPv4", "Unknown Protocol %i", hdr->Protocol); + return ; + } + + gaIPv4_Callbacks[hdr->Protocol]( iface, &hdr->Source, dataLength, data ); } /** * \fn tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address) * \brief Searches an adapter for a matching address + * \param Adapter Incoming Adapter + * \param Address Destination Address + * \param Broadcast Allow broadcast packets */ tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast) { tInterface *iface = NULL; Uint32 netmask; + Uint32 addr, this; + + addr = ntohl( Address.L ); for( iface = gIP_Interfaces; iface; iface = iface->Next) { if( iface->Adapter != Adapter ) continue; if( iface->Type != 4 ) continue; - if( IP4_EQU(Address, iface->IP4.Address) ) + if( IP4_EQU(Address, *(tIPv4*)iface->Address) ) return iface; if( !Broadcast ) continue; + this = ntohl( ((tIPv4*)iface->Address)->L ); + // Check for broadcast - netmask = IPv4_Netmask(iface->IP4.SubnetBits); - if( (Address.L & netmask) == (iface->IP4.Address.L & netmask) - && (Address.L & ~netmask) == (0xFFFFFFFF & ~netmask) ) + netmask = IPv4_Netmask(iface->SubnetBits); + + if( (addr & netmask) == (this & netmask) + && (addr & ~netmask) == (0xFFFFFFFF & ~netmask) ) return iface; } return NULL; @@ -92,13 +291,53 @@ tInterface *IPv4_GetInterface(tAdapter *Adapter, tIPv4 Address, int Broadcast) /** * \brief Convert a network prefix to a netmask + * \param FixedBits Netmask size (/n) * - * For example /24 will become 255.255.255.0 + * For example /24 will become 255.255.255.0 (0xFFFFFF00) */ Uint32 IPv4_Netmask(int FixedBits) { Uint32 ret = 0xFFFFFFFF; ret >>= (32-FixedBits); ret <<= (32-FixedBits); + // Returns a native endian netmask return ret; } + +/** + * \brief Calculate the IPv4 Checksum + * \param Buf Input buffer + * \param Size Size of input + * + * One's complement sum of all 16-bit words (bitwise inverted) + */ +Uint16 IPv4_Checksum(const void *Buf, size_t Length) +{ + const Uint16 *words = Buf; + Uint32 sum = 0; + int i; + + // Sum all whole words + for(i = 0; i < Length/2; i++ ) + { + sum += ntohs(words[i]); + } + if( Length & 1 ) + sum += ntohs( words[i] & 0xFF ); + + // Apply one's complement + while (sum >> 16) + sum = (sum & 0xFFFF) + (sum >> 16); + + return ~sum; +} + +/** + * \brief Sends an ICMP Echo and waits for a reply + * \param IFace Interface + * \param Addr Destination address + */ +int IPv4_Ping(tInterface *IFace, tIPv4 Addr) +{ + return ICMP_Ping(IFace, Addr); +}