/**************************************************************************** * net/ipfrag/ipv4_frag.c * Handling incoming IPv4 fragment input * * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. The * ASF licenses this file to you under the Apache License, Version 2.0 (the * "License"); you may not use this file except in compliance with the * License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the * License for the specific language governing permissions and limitations * under the License. * ****************************************************************************/ /**************************************************************************** * Included Files ****************************************************************************/ #include #if defined(CONFIG_NET_IPv4) && defined (CONFIG_NET_IPFRAG) #include #include #include #include #include #include #include #include #include #include #include #include #include #include "netdev/netdev.h" #include "inet/inet.h" #include "utils/utils.h" #include "ipfrag.h" /**************************************************************************** * Private Function Prototypes ****************************************************************************/ static inline int32_t ipv4_fragin_getinfo(FAR struct iob_s *iob, FAR struct ip_fraglink_s *fraglink); static uint32_t ipv4_fragin_reassemble(FAR struct ip_fragsnode_s *node); static inline void ipv4_fragout_buildipv4header(FAR struct ipv4_hdr_s *ref, FAR struct ipv4_hdr_s *ipv4, uint16_t len, uint16_t ipoff); /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: ipv4_fragin_getinfo * * Description: * Polulate fragment information from the input ipv4 packet data. * * Input Parameters: * iob - An IPv4 fragment * fraglink - node of the lower-level linked list, it maintains information * of one fragment * * Returned Value: * None * ****************************************************************************/ static inline int32_t ipv4_fragin_getinfo(FAR struct iob_s *iob, FAR struct ip_fraglink_s *fraglink) { FAR struct ipv4_hdr_s *ipv4 = (FAR struct ipv4_hdr_s *) (iob->io_data + iob->io_offset); uint16_t offset; fraglink->flink = NULL; fraglink->fragsnode = NULL; fraglink->isipv4 = true; offset = (ipv4->ipoffset[0] << 8) + ipv4->ipoffset[1]; fraglink->morefrags = offset & IP_FLAG_MOREFRAGS; fraglink->fragoff = ((offset & 0x1fff) << 3); fraglink->fraglen = (ipv4->len[0] << 8) + ipv4->len[1] - IPv4_HDRLEN; fraglink->ipid = (ipv4->ipid[0] << 8) + ipv4->ipid[1]; fraglink->frag = iob; return OK; } /**************************************************************************** * Name: ipv4_fragin_reassemble * * Description: * Reassemble all ipv4 fragments to build an IP frame. * * Input Parameters: * node - node of the upper-level linked list, it maintains * information about all fragments belonging to an IP datagram * * Returned Value: * The length of the reassembled IP frame * ****************************************************************************/ static uint32_t ipv4_fragin_reassemble(FAR struct ip_fragsnode_s *node) { FAR struct iob_s *head = NULL; FAR struct ipv4_hdr_s *ipv4; FAR struct ip_fraglink_s *fraglink; /* Loop to walk through the fragment list and reassemble those fragments, * the fraglink list was ordered by fragment offset value */ fraglink = node->frags; node->frags = NULL; while (fraglink != NULL) { FAR struct ip_fraglink_s *linknext; FAR struct iob_s *iob = fraglink->frag; if (fraglink->fragoff != 0) { uint16_t iphdrlen; /* Get IPv4 header length from IPv4 header (it may carry some * IPv4 options) */ ipv4 = (FAR struct ipv4_hdr_s *)(head->io_data + head->io_offset); iphdrlen = (ipv4->vhl & IPv4_HLMASK) << 2; /* Just modify the offset and length of all none zero fragments */ iob->io_offset += iphdrlen; iob->io_len -= iphdrlen; iob->io_pktlen -= iphdrlen; /* Concatenate this iob to the reassembly chain */ iob_concat(head, iob); } else { /* Remember the head iob */ head = iob; } linknext = fraglink->flink; kmm_free(fraglink); fraglink = linknext; } /* Remember the reassembled outgoing IP frame */ node->outgoframe = head; /* Get pointer of the new IPv4 header */ ipv4 = (FAR struct ipv4_hdr_s *)(head->io_data + head->io_offset); /* Update the length value in the IP Header */ ipv4->len[0] = head->io_pktlen >> 8; ipv4->len[1] = head->io_pktlen & 0xff; /* Set ipoffset to zero */ ipv4->ipoffset[0] = 0; ipv4->ipoffset[1] = 0; /* Calculate IP checksum. */ ipv4->ipchksum = 0; ipv4->ipchksum = ~(ipv4_chksum(ipv4)); return head->io_pktlen; } /**************************************************************************** * Name: ipv4_fragout_buildipv4header * * Description: * Build IPv4 header for an IPv4 fragment. * * Input Parameters: * ref - The reference IPv4 Header * ipv4 - The pointer of the newly generated IPv4 Header * len - Total Length of this IP frame * ipoff - Fragment offset * * Returned Value: * None * ****************************************************************************/ static inline void ipv4_fragout_buildipv4header(FAR struct ipv4_hdr_s *ref, FAR struct ipv4_hdr_s *ipv4, uint16_t len, uint16_t ipoff) { if (ref != ipv4) { uint32_t iphdrlen = (ref->vhl & IPv4_HLMASK) << 2; memcpy(ipv4, ref, iphdrlen); } ipv4->len[0] = len >> 8; ipv4->len[1] = len & 0xff; ipv4->ipoffset[0] = ipoff >> 8; ipv4->ipoffset[1] = ipoff & 0xff; /* Calculate IP checksum. */ ipv4->ipchksum = 0; ipv4->ipchksum = ~(ipv4_chksum(ipv4)); } /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: ipv4_fragin * * Description: * Handling incoming IPv4 and IPv6 fragment input, the input data * (dev->d_iob) can be an I/O buffer chain * * Input Parameters: * dev - The NIC device that the fragmented data comes from * * Returned Value: * ENOMEM - No memory * OK - The input fragment is processed as expected * ****************************************************************************/ int32_t ipv4_fragin(FAR struct net_driver_s *dev) { FAR struct ip_fragsnode_s *node; FAR struct ip_fraglink_s *fraginfo; bool restartwdog; if (dev->d_len != dev->d_iob->io_pktlen) { nerr("ERROR: Parameters error.\n"); return -EINVAL; } fraginfo = kmm_malloc(sizeof(struct ip_fraglink_s)); if (fraginfo == NULL) { nerr("ERROR: Failed to allocate buffer.\n"); return -ENOMEM; } /* Polulate fragment information from input packet data */ ipv4_fragin_getinfo(dev->d_iob, fraginfo); nxmutex_lock(&g_ipfrag_lock); /* Need to restart reassembly worker if the original linked list is empty */ restartwdog = ip_fragin_enqueue(dev, fraginfo); node = fraginfo->fragsnode; if (node->verifyflag & IP_FRAGVERIFY_RECVDALLFRAGS) { /* Well, all fragments of an IP frame have been received, remove * node from link list first, then reassemble and dispatch to the * stack. */ ip_frag_remnode(node); /* All fragments belonging to one IP frame have been separated * from the fragment processing module, unlocks mutex as soon * as possible */ nxmutex_unlock(&g_ipfrag_lock); /* Reassemble fragments to one IP frame and set the resulting * IP frame to dev->d_iob */ ipv4_fragin_reassemble(node); netdev_iob_replace(dev, node->outgoframe); /* Free the memory of node */ kmm_free(node); return ipv4_input(dev); } nxmutex_unlock(&g_ipfrag_lock); if (restartwdog) { /* Restart the work queue for fragment processing */ ip_frag_startwdog(); } return OK; } /**************************************************************************** * Name: ipv4_fragout * * Description: * Execute the ipv4 fragment function. After this work is done, all * fragments are maintained by dev->d_fragout. In order to reduce the * cyclomatic complexity and facilitate maintenance, fragmentation is * performed in two steps: * 1. Reconstruct I/O Buffer according to MTU, which will reserve * the space for the L3 header; * 2. Fill the L3 header into the reserved space. * * Input Parameters: * dev - The NIC device * mtu - The MTU of current NIC * * Returned Value: * 0 if success or a negative value if fail. * * Assumptions: * Data length(dev->d_iob->io_pktlen) is grater than the MTU of * current NIC * ****************************************************************************/ int32_t ipv4_fragout(FAR struct net_driver_s *dev, uint16_t mtu) { uint32_t iter; uint32_t nfrags; uint16_t offset = 0; uint16_t hdrlen; FAR struct iob_s *frag; FAR struct ipv4_hdr_s *ref = NULL; struct iob_queue_s fragq = { NULL, NULL }; /* Get the total length of L3 Header(if IPv4 options are present, then this * length includes the size of all the IPv4 options) */ hdrlen = (IPv4BUF->vhl & IPv4_HLMASK) << 2; /* Reconstruct I/O Buffer according to MTU, which will reserve * the space for the L3 header */ nfrags = ip_fragout_slice(dev->d_iob, PF_INET, mtu, hdrlen, &fragq); ASSERT(nfrags > 1); netdev_iob_clear(dev); /* Fill the L3 header into the reserved space */ for (iter = 0; iter < nfrags; iter++) { frag = iob_remove_queue(&fragq); if (iter == 0) { ref = (FAR struct ipv4_hdr_s *)(frag->io_data + frag->io_offset); /* Update the IPv4 header of the first fragment */ ipv4_fragout_buildipv4header(ref, ref, frag->io_pktlen, IP_FLAG_MOREFRAGS); } else { uint16_t ipoff = (offset - iter * hdrlen) >> 3; if (iter < nfrags - 1) { ipoff |= IP_FLAG_MOREFRAGS; } /* Refer to the zero fragment ipv4 header to construct the ipv4 * header of non-zero fragment */ ipv4_fragout_buildipv4header(ref, (FAR struct ipv4_hdr_s *)(frag->io_data + frag->io_offset), frag->io_pktlen, ipoff); } /* Enqueue this fragment to dev->d_fragout */ if (iob_tryadd_queue(frag, &dev->d_fragout) < 0) { goto fail; } offset += frag->io_pktlen; } #ifdef CONFIG_NET_STATISTICS g_netstats.ipv4.sent += nfrags - 1; #endif netdev_txnotify_dev(dev); return OK; fail: netdev_iob_release(dev); iob_free_chain(frag); iob_free_queue(&fragq); iob_free_queue(&dev->d_fragout); return -ENOMEM; } #endif /* CONFIG_NET_IPv4 && CONFIG_NET_IPFRAG */