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Added fragment reassembly code
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eb091f03e3
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@ -8,18 +8,25 @@
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*/
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#include <ip.h>
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#include <gpxe/retry.h>
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/* IP constants */
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#define IP_VER 4
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#define IP_MASK_VER 0xf0
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#define IP_MASK_HLEN 0x0f
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#define IP_MASK_OFFSET 0x1fff
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#define IP_MASK_DONOTFRAG 0x4000
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#define IP_MASK_MOREFRAGS 0x2000
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#define IP_PSHLEN 12
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/* IP header defaults */
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#define IP_TOS 0
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#define IP_TTL 64
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#define IP_FRAG_PKB_SIZE 1500
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#define IP_FRAG_TIMEOUT 50
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/* IP4 pseudo header */
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struct ipv4_pseudo_header {
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struct in_addr src;
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@ -29,6 +36,22 @@ struct ipv4_pseudo_header {
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uint16_t len;
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};
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/* Fragment reassembly buffer */
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struct frag_buffer {
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/* Identification number */
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uint16_t ident;
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/* Source network address */
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struct in_addr src;
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/* Destination network address */
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struct in_addr dest;
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/* Reassembled packet buffer */
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struct pk_buff *frag_pkb;
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/* Reassembly timer */
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struct retry_timer frag_timer;
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/* List of fragment reassembly buffers */
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struct list_head list;
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};
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struct pk_buff;
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struct net_device;
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struct net_protocol;
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123
src/net/ipv4.c
123
src/net/ipv4.c
@ -47,6 +47,9 @@ struct ipv4_miniroute {
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/** List of IPv4 miniroutes */
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static LIST_HEAD ( miniroutes );
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/** List of fragment reassembly buffers */
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static LIST_HEAD ( frag_buffers );
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/**
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* Add IPv4 interface
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*
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@ -119,6 +122,110 @@ static void ipv4_dump ( struct iphdr *iphdr __unused ) {
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DBG ( "\tDestination = %s\n", inet_ntoa ( iphdr->dest ) );
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}
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/**
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* Fragment reassembly counter timeout
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*
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* @v timer Retry timer
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* @v over If asserted, the timer is greater than @c MAX_TIMEOUT
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*/
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void ipv4_frag_expired ( struct retry_timer *timer __unused , int over ) {
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if ( over ) {
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DBG ( "Fragment reassembly timeout" );
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/* Free the fragment buffer */
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}
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}
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/**
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* Free fragment buffer
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*
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* @v fragbug Fragment buffer
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*/
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void free_fragbuf ( struct frag_buffer *fragbuf ) {
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if ( fragbuf ) {
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free_dma ( fragbuf, sizeof ( *fragbuf ) );
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}
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}
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/**
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* Fragment reassembler
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*
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* @v pkb Packet buffer, fragment of the datagram
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* @ret frag_pkb Reassembled packet, or NULL
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*/
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struct pk_buff * ipv4_reassemble ( struct pk_buff * pkb ) {
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struct iphdr *iphdr = pkb->data;
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struct frag_buffer *fragbuf;
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/**
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* Check if the fragment belongs to any fragment series
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*/
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list_for_each_entry ( fragbuf, &frag_buffers, list ) {
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if ( fragbuf->ident == iphdr->ident &&
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fragbuf->src.s_addr == iphdr->src.s_addr ) {
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/**
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* Check if the packet is the expected fragment
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*
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* The offset of the new packet must be equal to the
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* length of the data accumulated so far (the length of
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* the reassembled packet buffer
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*/
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if ( pkb_len ( fragbuf->frag_pkb ) ==
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( iphdr->frags & IP_MASK_OFFSET ) ) {
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/**
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* Append the contents of the fragment to the
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* reassembled packet buffer
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*/
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pkb_pull ( pkb, sizeof ( *iphdr ) );
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memcpy ( pkb_put ( fragbuf->frag_pkb,
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pkb_len ( pkb ) ),
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pkb->data, pkb_len ( pkb ) );
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free_pkb ( pkb );
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/** Check if the fragment series is over */
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if ( !iphdr->frags & IP_MASK_MOREFRAGS ) {
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pkb = fragbuf->frag_pkb;
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free_fragbuf ( fragbuf );
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return pkb;
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}
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} else {
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/* Discard the fragment series */
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free_fragbuf ( fragbuf );
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free_pkb ( pkb );
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}
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return NULL;
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}
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}
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/** Check if the fragment is the first in the fragment series */
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if ( iphdr->frags & IP_MASK_MOREFRAGS &&
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( ( iphdr->frags & IP_MASK_OFFSET ) == 0 ) ) {
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/** Create a new fragment buffer */
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fragbuf = ( struct frag_buffer* ) malloc ( sizeof( *fragbuf ) );
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fragbuf->ident = iphdr->ident;
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fragbuf->src = iphdr->src;
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/* Set up the reassembly packet buffer */
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fragbuf->frag_pkb = alloc_pkb ( IP_FRAG_PKB_SIZE );
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pkb_pull ( pkb, sizeof ( *iphdr ) );
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memcpy ( pkb_put ( fragbuf->frag_pkb, pkb_len ( pkb ) ),
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pkb->data, pkb_len ( pkb ) );
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free_pkb ( pkb );
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/* Set the reassembly timer */
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fragbuf->frag_timer.timeout = IP_FRAG_TIMEOUT;
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fragbuf->frag_timer.expired = ipv4_frag_expired;
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start_timer ( &fragbuf->frag_timer );
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/* Add the fragment buffer to the list of fragment buffers */
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list_add ( &fragbuf->list, &frag_buffers );
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}
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return NULL;
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}
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/**
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* Complete the transport-layer checksum
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*
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@ -294,7 +401,9 @@ int ipv4_tx ( struct pk_buff *pkb, struct tcpip_protocol *tcpip,
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}
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/* Calculate the transport layer checksum */
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ipv4_tx_csum ( pkb, tcpip );
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if ( tcpip->csum_offset > 0 ) {
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ipv4_tx_csum ( pkb, tcpip );
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}
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/* Calculate header checksum, in network byte order */
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iphdr->chksum = 0;
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@ -416,6 +525,18 @@ void ipv4_rx ( struct pk_buff *pkb, struct net_device *netdev __unused,
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if ( ( chksum = ipv4_rx_csum ( pkb, iphdr->protocol ) ) != 0xffff ) {
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DBG ( "Bad checksum %x\n", chksum );
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}
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/* Fragment reassembly */
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if ( iphdr->frags & IP_MASK_MOREFRAGS ||
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( !iphdr->frags & IP_MASK_MOREFRAGS &&
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iphdr->frags & IP_MASK_OFFSET != 0 ) ) {
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/* Pass the fragment to the reassembler ipv4_ressable() which
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* either returns a fully reassembled packet buffer or NULL.
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*/
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pkb = ipv4_reassemble ( pkb );
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if ( !pkb ) {
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return;
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}
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}
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/* To reduce code size, the following functions are not implemented:
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* 1. Check the destination address
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@ -22,19 +22,14 @@ static inline void copy_sockaddr ( struct sockaddr *source, struct sockaddr *des
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memcpy ( dest, source, sizeof ( *dest ) );
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}
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static inline uint16_t dest_port ( struct sockaddr *sock, uint16_t *dest ) {
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static inline uint16_t * dest_port ( struct sockaddr *sock ) {
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switch ( sock->sa_family ) {
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case AF_INET:
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dest = &sock->sin.sin_port;
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break;
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return &sock->sin.sin_port;
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case AF_INET6:
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dest = &sock->sin6.sin6_port;
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break;
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default:
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DBG ( "Network family %d not supported\n", sock->sa_family );
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return -EAFNOSUPPORT;
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return &sock->sin6.sin6_port;
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}
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return 0;
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return NULL;
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}
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/**
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@ -49,7 +44,7 @@ void udp_dump ( struct udp_header *udphdr ) {
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DBG ( "\tSource Port = %d\n", ntohs ( udphdr->source_port ) );
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DBG ( "\tDestination Port = %d\n", ntohs ( udphdr->dest_port ) );
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DBG ( "\tLength = %d\n", ntohs ( udphdr->len ) );
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DBG ( "\tChecksum = %d\n", ntohs ( udphdr->chksum ) );
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DBG ( "\tChecksum = %x\n", ntohs ( udphdr->chksum ) );
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DBG ( "\tChecksum located at %#x\n", &udphdr->chksum );
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}
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@ -139,11 +134,12 @@ int udp_send ( struct udp_connection *conn, const void *data, size_t len ) {
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* sending it over the network
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*/
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udphdr = pkb_push ( conn->tx_pkb, sizeof ( *udphdr ) );
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if ( (rc = dest_port ( sock, dest ) ) != 0 ) {
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return rc;
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if ( (dest = dest_port ( sock ) ) == NULL ) {
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DBG ( "Network family %d not supported\n", sock->sa_family );
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return -EAFNOSUPPORT;
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}
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udphdr->dest_port = htons ( *dest );
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udphdr->source_port = htons ( conn->local_port );
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udphdr->dest_port = *dest;
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udphdr->source_port = conn->local_port;
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udphdr->len = htons ( pkb_len ( conn->tx_pkb ) );
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udphdr->chksum = htons ( calc_chksum ( udphdr, sizeof ( *udphdr ) ) );
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