cregit-Linux how code gets into the kernel

Release 4.8 net/ieee802154/6lowpan/reassembly.c

/*      6LoWPAN fragment reassembly
 *
 *
 *      Authors:
 *      Alexander Aring         <aar@pengutronix.de>
 *
 *      Based on: net/ipv6/reassembly.c
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */


#define pr_fmt(fmt) "6LoWPAN: " fmt

#include <linux/net.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/random.h>
#include <linux/jhash.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/export.h>

#include <net/ieee802154_netdev.h>
#include <net/6lowpan.h>
#include <net/ipv6.h>
#include <net/inet_frag.h>

#include "6lowpan_i.h"


static const char lowpan_frags_cache_name[] = "lowpan-frags";


static struct inet_frags lowpan_frags;

static int lowpan_frag_reasm(struct lowpan_frag_queue *fq,
			     struct sk_buff *prev, struct net_device *ldev);


static unsigned int lowpan_hash_frag(u16 tag, u16 d_size, const struct ieee802154_addr *saddr, const struct ieee802154_addr *daddr) { net_get_random_once(&lowpan_frags.rnd, sizeof(lowpan_frags.rnd)); return jhash_3words(ieee802154_addr_hash(saddr), ieee802154_addr_hash(daddr), (__force u32)(tag + (d_size << 16)), lowpan_frags.rnd); }

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alexander aringalexander aring6995.83%360.00%
phoebe buckheisterphoebe buckheister22.78%120.00%
florian westphalflorian westphal11.39%120.00%
Total72100.00%5100.00%


static unsigned int lowpan_hashfn(const struct inet_frag_queue *q) { const struct lowpan_frag_queue *fq; fq = container_of(q, struct lowpan_frag_queue, q); return lowpan_hash_frag(fq->tag, fq->d_size, &fq->saddr, &fq->daddr); }

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alexander aringalexander aring5196.23%150.00%
florian westphalflorian westphal23.77%150.00%
Total53100.00%2100.00%


static bool lowpan_frag_match(const struct inet_frag_queue *q, const void *a) { const struct lowpan_frag_queue *fq; const struct lowpan_create_arg *arg = a; fq = container_of(q, struct lowpan_frag_queue, q); return fq->tag == arg->tag && fq->d_size == arg->d_size && ieee802154_addr_equal(&fq->saddr, arg->src) && ieee802154_addr_equal(&fq->daddr, arg->dst); }

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alexander aringalexander aring7791.67%125.00%
florian westphalflorian westphal55.95%250.00%
phoebe buckheisterphoebe buckheister22.38%125.00%
Total84100.00%4100.00%


static void lowpan_frag_init(struct inet_frag_queue *q, const void *a) { const struct lowpan_create_arg *arg = a; struct lowpan_frag_queue *fq; fq = container_of(q, struct lowpan_frag_queue, q); fq->tag = arg->tag; fq->d_size = arg->d_size; fq->saddr = *arg->src; fq->daddr = *arg->dst; }

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alexander aringalexander aring6789.33%133.33%
florian westphalflorian westphal810.67%266.67%
Total75100.00%3100.00%


static void lowpan_frag_expire(unsigned long data) { struct frag_queue *fq; struct net *net; fq = container_of((struct inet_frag_queue *)data, struct frag_queue, q); net = container_of(fq->q.net, struct net, ieee802154_lowpan.frags); spin_lock(&fq->q.lock); if (fq->q.flags & INET_FRAG_COMPLETE) goto out; inet_frag_kill(&fq->q, &lowpan_frags); out: spin_unlock(&fq->q.lock); inet_frag_put(&fq->q, &lowpan_frags); }

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alexander aringalexander aring6457.14%133.33%
florian westphalflorian westphal4741.96%133.33%
nikolay aleksandrovnikolay aleksandrov10.89%133.33%
Total112100.00%3100.00%


static inline struct lowpan_frag_queue * fq_find(struct net *net, const struct lowpan_802154_cb *cb, const struct ieee802154_addr *src, const struct ieee802154_addr *dst) { struct inet_frag_queue *q; struct lowpan_create_arg arg; unsigned int hash; struct netns_ieee802154_lowpan *ieee802154_lowpan = net_ieee802154_lowpan(net); arg.tag = cb->d_tag; arg.d_size = cb->d_size; arg.src = src; arg.dst = dst; hash = lowpan_hash_frag(cb->d_tag, cb->d_size, src, dst); q = inet_frag_find(&ieee802154_lowpan->frags, &lowpan_frags, &arg, hash); if (IS_ERR_OR_NULL(q)) { inet_frag_maybe_warn_overflow(q, pr_fmt()); return NULL; } return container_of(q, struct lowpan_frag_queue, q); }

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alexander aringalexander aring13691.28%250.00%
luis r. rodriguezluis r. rodriguez117.38%125.00%
phoebe buckheisterphoebe buckheister21.34%125.00%
Total149100.00%4100.00%


static int lowpan_frag_queue(struct lowpan_frag_queue *fq, struct sk_buff *skb, u8 frag_type) { struct sk_buff *prev, *next; struct net_device *ldev; int end, offset; if (fq->q.flags & INET_FRAG_COMPLETE) goto err; offset = lowpan_802154_cb(skb)->d_offset << 3; end = lowpan_802154_cb(skb)->d_size; /* Is this the final fragment? */ if (offset + skb->len == end) { /* If we already have some bits beyond end * or have different end, the segment is corrupted. */ if (end < fq->q.len || ((fq->q.flags & INET_FRAG_LAST_IN) && end != fq->q.len)) goto err; fq->q.flags |= INET_FRAG_LAST_IN; fq->q.len = end; } else { if (end > fq->q.len) { /* Some bits beyond end -> corruption. */ if (fq->q.flags & INET_FRAG_LAST_IN) goto err; fq->q.len = end; } } /* Find out which fragments are in front and at the back of us * in the chain of fragments so far. We must know where to put * this fragment, right? */ prev = fq->q.fragments_tail; if (!prev || lowpan_802154_cb(prev)->d_offset < lowpan_802154_cb(skb)->d_offset) { next = NULL; goto found; } prev = NULL; for (next = fq->q.fragments; next != NULL; next = next->next) { if (lowpan_802154_cb(next)->d_offset >= lowpan_802154_cb(skb)->d_offset) break; /* bingo! */ prev = next; } found: /* Insert this fragment in the chain of fragments. */ skb->next = next; if (!next) fq->q.fragments_tail = skb; if (prev) prev->next = skb; else fq->q.fragments = skb; ldev = skb->dev; if (ldev) skb->dev = NULL; fq->q.stamp = skb->tstamp; if (frag_type == LOWPAN_DISPATCH_FRAG1) fq->q.flags |= INET_FRAG_FIRST_IN; fq->q.meat += skb->len; add_frag_mem_limit(fq->q.net, skb->truesize); if (fq->q.flags == (INET_FRAG_FIRST_IN | INET_FRAG_LAST_IN) && fq->q.meat == fq->q.len) { int res; unsigned long orefdst = skb->_skb_refdst; skb->_skb_refdst = 0UL; res = lowpan_frag_reasm(fq, prev, ldev); skb->_skb_refdst = orefdst; return res; } return -1; err: kfree_skb(skb); return -1; }

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alexander aringalexander aring43198.18%360.00%
nikolay aleksandrovnikolay aleksandrov61.37%120.00%
florian westphalflorian westphal20.46%120.00%
Total439100.00%5100.00%

/* Check if this packet is complete. * Returns NULL on failure by any reason, and pointer * to current nexthdr field in reassembled frame. * * It is called with locked fq, and caller must check that * queue is eligible for reassembly i.e. it is not COMPLETE, * the last and the first frames arrived and all the bits are here. */
static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, struct sk_buff *prev, struct net_device *ldev) { struct sk_buff *fp, *head = fq->q.fragments; int sum_truesize; inet_frag_kill(&fq->q, &lowpan_frags); /* Make the one we just received the head. */ if (prev) { head = prev->next; fp = skb_clone(head, GFP_ATOMIC); if (!fp) goto out_oom; fp->next = head->next; if (!fp->next) fq->q.fragments_tail = fp; prev->next = fp; skb_morph(head, fq->q.fragments); head->next = fq->q.fragments->next; consume_skb(fq->q.fragments); fq->q.fragments = head; } /* Head of list must not be cloned. */ if (skb_unclone(head, GFP_ATOMIC)) goto out_oom; /* If the first fragment is fragmented itself, we split * it to two chunks: the first with data and paged part * and the second, holding only fragments. */ if (skb_has_frag_list(head)) { struct sk_buff *clone; int i, plen = 0; clone = alloc_skb(0, GFP_ATOMIC); if (!clone) goto out_oom; clone->next = head->next; head->next = clone; skb_shinfo(clone)->frag_list = skb_shinfo(head)->frag_list; skb_frag_list_init(head); for (i = 0; i < skb_shinfo(head)->nr_frags; i++) plen += skb_frag_size(&skb_shinfo(head)->frags[i]); clone->len = head->data_len - plen; clone->data_len = clone->len; head->data_len -= clone->len; head->len -= clone->len; add_frag_mem_limit(fq->q.net, clone->truesize); } WARN_ON(head == NULL); sum_truesize = head->truesize; for (fp = head->next; fp;) { bool headstolen; int delta; struct sk_buff *next = fp->next; sum_truesize += fp->truesize; if (skb_try_coalesce(head, fp, &headstolen, &delta)) { kfree_skb_partial(fp, headstolen); } else { if (!skb_shinfo(head)->frag_list) skb_shinfo(head)->frag_list = fp; head->data_len += fp->len; head->len += fp->len; head->truesize += fp->truesize; } fp = next; } sub_frag_mem_limit(fq->q.net, sum_truesize); head->next = NULL; head->dev = ldev; head->tstamp = fq->q.stamp; fq->q.fragments = NULL; fq->q.fragments_tail = NULL; return 1; out_oom: net_dbg_ratelimited("lowpan_frag_reasm: no memory for reassembly\n"); return -1; }

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alexander aringalexander aring49499.20%266.67%
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Total498100.00%3100.00%


static int lowpan_frag_rx_handlers_result(struct sk_buff *skb, lowpan_rx_result res) { switch (res) { case RX_QUEUED: return NET_RX_SUCCESS; case RX_CONTINUE: /* nobody cared about this packet */ net_warn_ratelimited("%s: received unknown dispatch\n", __func__); /* fall-through */ default: /* all others failure */ return NET_RX_DROP; } }

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alexander aringalexander aring43100.00%2100.00%
Total43100.00%2100.00%


static lowpan_rx_result lowpan_frag_rx_h_iphc(struct sk_buff *skb) { int ret; if (!lowpan_is_iphc(*skb_network_header(skb))) return RX_CONTINUE; ret = lowpan_iphc_decompress(skb); if (ret < 0) return RX_DROP; return RX_QUEUED; }

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alexander aringalexander aring48100.00%1100.00%
Total48100.00%1100.00%


static int lowpan_invoke_frag_rx_handlers(struct sk_buff *skb) { lowpan_rx_result res; #define CALL_RXH(rxh) \ do { \ res = rxh(skb); \ if (res != RX_CONTINUE) \ goto rxh_next; \ } while (0) /* likely at first */ CALL_RXH(lowpan_frag_rx_h_iphc); CALL_RXH(lowpan_rx_h_ipv6); rxh_next: return lowpan_frag_rx_handlers_result(skb, res); #undef CALL_RXH }

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alexander aringalexander aring46100.00%1100.00%
Total46100.00%1100.00%

#define LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK 0x07 #define LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT 8
static int lowpan_get_cb(struct sk_buff *skb, u8 frag_type, struct lowpan_802154_cb *cb) { bool fail; u8 high = 0, low = 0; __be16 d_tag = 0; fail = lowpan_fetch_skb(skb, &high, 1); fail |= lowpan_fetch_skb(skb, &low, 1); /* remove the dispatch value and use first three bits as high value * for the datagram size */ cb->d_size = (high & LOWPAN_FRAG_DGRAM_SIZE_HIGH_MASK) << LOWPAN_FRAG_DGRAM_SIZE_HIGH_SHIFT | low; fail |= lowpan_fetch_skb(skb, &d_tag, 2); cb->d_tag = ntohs(d_tag); if (frag_type == LOWPAN_DISPATCH_FRAGN) { fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1); } else { skb_reset_network_header(skb); cb->d_offset = 0; /* check if datagram_size has ipv6hdr on FRAG1 */ fail |= cb->d_size < sizeof(struct ipv6hdr); /* check if we can dereference the dispatch value */ fail |= !skb->len; } if (unlikely(fail)) return -EIO; return 0; }

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alexander aringalexander aring167100.00%3100.00%
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int lowpan_frag_rcv(struct sk_buff *skb, u8 frag_type) { struct lowpan_frag_queue *fq; struct net *net = dev_net(skb->dev); struct lowpan_802154_cb *cb = lowpan_802154_cb(skb); struct ieee802154_hdr hdr; int err; if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0) goto err; err = lowpan_get_cb(skb, frag_type, cb); if (err < 0) goto err; if (frag_type == LOWPAN_DISPATCH_FRAG1) { err = lowpan_invoke_frag_rx_handlers(skb); if (err == NET_RX_DROP) goto err; } if (cb->d_size > IPV6_MIN_MTU) { net_warn_ratelimited("lowpan_frag_rcv: datagram size exceeds MTU\n"); goto err; } fq = fq_find(net, cb, &hdr.source, &hdr.dest); if (fq != NULL) { int ret; spin_lock(&fq->q.lock); ret = lowpan_frag_queue(fq, skb, frag_type); spin_unlock(&fq->q.lock); inet_frag_put(&fq->q, &lowpan_frags); return ret; } err: kfree_skb(skb); return -1; }

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alexander aringalexander aring19592.86%250.00%
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phoebe buckheisterphoebe buckheister73.33%125.00%
Total210100.00%4100.00%

#ifdef CONFIG_SYSCTL static int zero; static struct ctl_table lowpan_frags_ns_ctl_table[] = { { .procname = "6lowpanfrag_high_thresh", .data = &init_net.ieee802154_lowpan.frags.high_thresh, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = &init_net.ieee802154_lowpan.frags.low_thresh }, { .procname = "6lowpanfrag_low_thresh", .data = &init_net.ieee802154_lowpan.frags.low_thresh, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec_minmax, .extra1 = &zero, .extra2 = &init_net.ieee802154_lowpan.frags.high_thresh }, { .procname = "6lowpanfrag_time", .data = &init_net.ieee802154_lowpan.frags.timeout, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec_jiffies, }, { } }; /* secret interval has been deprecated */ static int lowpan_frags_secret_interval_unused; static struct ctl_table lowpan_frags_ctl_table[] = { { .procname = "6lowpanfrag_secret_interval", .data = &lowpan_frags_secret_interval_unused, .maxlen = sizeof(int), .mode = 0644, .proc_handler = proc_dointvec_jiffies, }, { } };
static int __net_init lowpan_frags_ns_sysctl_register(struct net *net) { struct ctl_table *table; struct ctl_table_header *hdr; struct netns_ieee802154_lowpan *ieee802154_lowpan = net_ieee802154_lowpan(net); table = lowpan_frags_ns_ctl_table; if (!net_eq(net, &init_net)) { table = kmemdup(table, sizeof(lowpan_frags_ns_ctl_table), GFP_KERNEL); if (table == NULL) goto err_alloc; table[0].data = &ieee802154_lowpan->frags.high_thresh; table[0].extra1 = &ieee802154_lowpan->frags.low_thresh; table[0].extra2 = &init_net.ieee802154_lowpan.frags.high_thresh; table[1].data = &ieee802154_lowpan->frags.low_thresh; table[1].extra2 = &ieee802154_lowpan->frags.high_thresh; table[2].data = &ieee802154_lowpan->frags.timeout; /* Don't export sysctls to unprivileged users */ if (net->user_ns != &init_user_ns) table[0].procname = NULL; } hdr = register_net_sysctl(net, "net/ieee802154/6lowpan", table); if (hdr == NULL) goto err_reg; ieee802154_lowpan->sysctl.frags_hdr = hdr; return 0; err_reg: if (!net_eq(net, &init_net)) kfree(table); err_alloc: return -ENOMEM; }

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alexander aringalexander aring17475.00%133.33%
nikolay aleksandrovnikolay aleksandrov4418.97%133.33%
luis r. rodriguezluis r. rodriguez146.03%133.33%
Total232100.00%3100.00%


static void __net_exit lowpan_frags_ns_sysctl_unregister(struct net *net) { struct ctl_table *table; struct netns_ieee802154_lowpan *ieee802154_lowpan = net_ieee802154_lowpan(net); table = ieee802154_lowpan->sysctl.frags_hdr->ctl_table_arg; unregister_net_sysctl_table(ieee802154_lowpan->sysctl.frags_hdr); if (!net_eq(net, &init_net)) kfree(table); }

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alexander aringalexander aring5080.65%150.00%
luis r. rodriguezluis r. rodriguez1219.35%150.00%
Total62100.00%2100.00%

static struct ctl_table_header *lowpan_ctl_header;
static int __init lowpan_frags_sysctl_register(void) { lowpan_ctl_header = register_net_sysctl(&init_net, "net/ieee802154/6lowpan", lowpan_frags_ctl_table); return lowpan_ctl_header == NULL ? -ENOMEM : 0; }

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alexander aringalexander aring3096.77%150.00%
fabian frederickfabian frederick13.23%150.00%
Total31100.00%2100.00%


static void lowpan_frags_sysctl_unregister(void) { unregister_net_sysctl_table(lowpan_ctl_header); }

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alexander aringalexander aring13100.00%1100.00%
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#else
static inline int lowpan_frags_ns_sysctl_register(struct net *net) { return 0; }

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alexander aringalexander aring15100.00%1100.00%
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static inline void lowpan_frags_ns_sysctl_unregister(struct net *net) { }

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alexander aringalexander aring11100.00%1100.00%
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static inline int __init lowpan_frags_sysctl_register(void) { return 0; }

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alexander aringalexander aring1292.31%150.00%
fabian frederickfabian frederick17.69%150.00%
Total13100.00%2100.00%


static inline void lowpan_frags_sysctl_unregister(void) { }

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alexander aringalexander aring8100.00%1100.00%
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#endif
static int __net_init lowpan_frags_init_net(struct net *net) { struct netns_ieee802154_lowpan *ieee802154_lowpan = net_ieee802154_lowpan(net); int res; ieee802154_lowpan->frags.high_thresh = IPV6_FRAG_HIGH_THRESH; ieee802154_lowpan->frags.low_thresh = IPV6_FRAG_LOW_THRESH; ieee802154_lowpan->frags.timeout = IPV6_FRAG_TIMEOUT; res = inet_frags_init_net(&ieee802154_lowpan->frags); if (res) return res; res = lowpan_frags_ns_sysctl_register(net); if (res) inet_frags_uninit_net(&ieee802154_lowpan->frags); return res; }

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alexander aringalexander aring4753.41%133.33%
eric dumazeteric dumazet2831.82%133.33%
luis r. rodriguezluis r. rodriguez1314.77%133.33%
Total88100.00%3100.00%


static void __net_exit lowpan_frags_exit_net(struct net *net) { struct netns_ieee802154_lowpan *ieee802154_lowpan = net_ieee802154_lowpan(net); lowpan_frags_ns_sysctl_unregister(net); inet_frags_exit_net(&ieee802154_lowpan->frags, &lowpan_frags); }

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alexander aringalexander aring2771.05%150.00%
luis r. rodriguezluis r. rodriguez1128.95%150.00%
Total38100.00%2100.00%

static struct pernet_operations lowpan_frags_ops = { .init = lowpan_frags_init_net