diff options
| -rw-r--r-- | net/6lowpan/Makefile | 2 | ||||
| -rw-r--r-- | net/6lowpan/nhc.c | 241 | ||||
| -rw-r--r-- | net/6lowpan/nhc.h | 146 |
3 files changed, 388 insertions, 1 deletions
diff --git a/net/6lowpan/Makefile b/net/6lowpan/Makefile index 415886b..4215602 100644 --- a/net/6lowpan/Makefile +++ b/net/6lowpan/Makefile @@ -1,3 +1,3 @@ obj-$(CONFIG_6LOWPAN) := 6lowpan.o -6lowpan-y := iphc.o +6lowpan-y := iphc.o nhc.o diff --git a/net/6lowpan/nhc.c b/net/6lowpan/nhc.c new file mode 100644 index 0000000..fd20fc5 --- /dev/null +++ b/net/6lowpan/nhc.c @@ -0,0 +1,241 @@ +/* + * 6LoWPAN next header compression + * + * + * Authors: + * Alexander Aring <aar@pengutronix.de> + * + * 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. + */ + +#include <linux/netdevice.h> + +#include <net/ipv6.h> + +#include "nhc.h" + +static struct rb_root rb_root = RB_ROOT; +static struct lowpan_nhc *lowpan_nexthdr_nhcs[NEXTHDR_MAX]; +static DEFINE_SPINLOCK(lowpan_nhc_lock); + +static int lowpan_nhc_insert(struct lowpan_nhc *nhc) +{ + struct rb_node **new = &rb_root.rb_node, *parent = NULL; + + /* Figure out where to put new node */ + while (*new) { + struct lowpan_nhc *this = container_of(*new, struct lowpan_nhc, + node); + int result, len_dif, len; + + len_dif = nhc->idlen - this->idlen; + + if (nhc->idlen < this->idlen) + len = nhc->idlen; + else + len = this->idlen; + + result = memcmp(nhc->id, this->id, len); + if (!result) + result = len_dif; + + parent = *new; + if (result < 0) + new = &((*new)->rb_left); + else if (result > 0) + new = &((*new)->rb_right); + else + return -EEXIST; + } + + /* Add new node and rebalance tree. */ + rb_link_node(&nhc->node, parent, new); + rb_insert_color(&nhc->node, &rb_root); + + return 0; +} + +static void lowpan_nhc_remove(struct lowpan_nhc *nhc) +{ + rb_erase(&nhc->node, &rb_root); +} + +static struct lowpan_nhc *lowpan_nhc_by_nhcid(const struct sk_buff *skb) +{ + struct rb_node *node = rb_root.rb_node; + const u8 *nhcid_skb_ptr = skb->data; + + while (node) { + struct lowpan_nhc *nhc = container_of(node, struct lowpan_nhc, + node); + u8 nhcid_skb_ptr_masked[LOWPAN_NHC_MAX_ID_LEN]; + int result, i; + + if (nhcid_skb_ptr + nhc->idlen > skb->data + skb->len) + return NULL; + + /* copy and mask afterwards the nhid value from skb */ + memcpy(nhcid_skb_ptr_masked, nhcid_skb_ptr, nhc->idlen); + for (i = 0; i < nhc->idlen; i++) + nhcid_skb_ptr_masked[i] &= nhc->idmask[i]; + + result = memcmp(nhcid_skb_ptr_masked, nhc->id, nhc->idlen); + if (result < 0) + node = node->rb_left; + else if (result > 0) + node = node->rb_right; + else + return nhc; + } + + return NULL; +} + +int lowpan_nhc_check_compression(struct sk_buff *skb, + const struct ipv6hdr *hdr, u8 **hc_ptr, + u8 *iphc0) +{ + struct lowpan_nhc *nhc; + + spin_lock_bh(&lowpan_nhc_lock); + + nhc = lowpan_nexthdr_nhcs[hdr->nexthdr]; + if (nhc && nhc->compress) + *iphc0 |= LOWPAN_IPHC_NH_C; + else + lowpan_push_hc_data(hc_ptr, &hdr->nexthdr, + sizeof(hdr->nexthdr)); + + spin_unlock_bh(&lowpan_nhc_lock); + + return 0; +} + +int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr, + u8 **hc_ptr) +{ + int ret; + struct lowpan_nhc *nhc; + + spin_lock_bh(&lowpan_nhc_lock); + + nhc = lowpan_nexthdr_nhcs[hdr->nexthdr]; + /* check if the nhc module was removed in unlocked part. + * TODO: this is a workaround we should prevent unloading + * of nhc modules while unlocked part, this will always drop + * the lowpan packet but it's very unlikely. + * + * Solution isn't easy because we need to decide at + * lowpan_nhc_check_compression if we do a compression or not. + * Because the inline data which is added to skb, we can't move this + * handling. + */ + if (unlikely(!nhc || !nhc->compress)) { + ret = -EINVAL; + goto out; + } + + /* In the case of RAW sockets the transport header is not set by + * the ip6 stack so we must set it ourselves + */ + if (skb->transport_header == skb->network_header) + skb_set_transport_header(skb, sizeof(struct ipv6hdr)); + + ret = nhc->compress(skb, hc_ptr); + if (ret < 0) + goto out; + + /* skip the transport header */ + skb_pull(skb, nhc->nexthdrlen); + +out: + spin_unlock_bh(&lowpan_nhc_lock); + + return ret; +} + +int lowpan_nhc_do_uncompression(struct sk_buff *skb, struct net_device *dev, + struct ipv6hdr *hdr) +{ + struct lowpan_nhc *nhc; + int ret; + + spin_lock_bh(&lowpan_nhc_lock); + + nhc = lowpan_nhc_by_nhcid(skb); + if (nhc) { + if (nhc->uncompress) { + ret = nhc->uncompress(skb, sizeof(struct ipv6hdr) + + nhc->nexthdrlen); + if (ret < 0) { + spin_unlock_bh(&lowpan_nhc_lock); + return ret; + } + } else { + spin_unlock_bh(&lowpan_nhc_lock); + netdev_warn(dev, "received nhc id for %s which is not implemented.\n", + nhc->name); + return -ENOTSUPP; + } + } else { + spin_unlock_bh(&lowpan_nhc_lock); + netdev_warn(dev, "received unknown nhc id which was not found.\n"); + return -ENOENT; + } + + hdr->nexthdr = nhc->nexthdr; + skb_reset_transport_header(skb); + raw_dump_table(__func__, "raw transport header dump", + skb_transport_header(skb), nhc->nexthdrlen); + + spin_unlock_bh(&lowpan_nhc_lock); + + return 0; +} + +int lowpan_nhc_add(struct lowpan_nhc *nhc) +{ + int ret; + + if (!nhc->idlen || !nhc->idsetup) + return -EINVAL; + + WARN_ONCE(nhc->idlen > LOWPAN_NHC_MAX_ID_LEN, + "LOWPAN_NHC_MAX_ID_LEN should be updated to %zd.\n", + nhc->idlen); + + nhc->idsetup(nhc); + + spin_lock_bh(&lowpan_nhc_lock); + + if (lowpan_nexthdr_nhcs[nhc->nexthdr]) { + ret = -EEXIST; + goto out; + } + + ret = lowpan_nhc_insert(nhc); + if (ret < 0) + goto out; + + lowpan_nexthdr_nhcs[nhc->nexthdr] = nhc; +out: + spin_unlock_bh(&lowpan_nhc_lock); + return ret; +} +EXPORT_SYMBOL(lowpan_nhc_add); + +void lowpan_nhc_del(struct lowpan_nhc *nhc) +{ + spin_lock_bh(&lowpan_nhc_lock); + + lowpan_nhc_remove(nhc); + lowpan_nexthdr_nhcs[nhc->nexthdr] = NULL; + + spin_unlock_bh(&lowpan_nhc_lock); + + synchronize_net(); +} +EXPORT_SYMBOL(lowpan_nhc_del); diff --git a/net/6lowpan/nhc.h b/net/6lowpan/nhc.h new file mode 100644 index 0000000..ed44938 --- /dev/null +++ b/net/6lowpan/nhc.h @@ -0,0 +1,146 @@ +#ifndef __6LOWPAN_NHC_H +#define __6LOWPAN_NHC_H + +#include <linux/skbuff.h> +#include <linux/rbtree.h> +#include <linux/module.h> + +#include <net/6lowpan.h> +#include <net/ipv6.h> + +#define LOWPAN_NHC_MAX_ID_LEN 1 + +/** + * LOWPAN_NHC - helper macro to generate nh id fields and lowpan_nhc struct + * + * @__nhc: variable name of the lowpan_nhc struct. + * @_name: const char * of common header compression name. + * @_nexthdr: ipv6 nexthdr field for the header compression. + * @_nexthdrlen: ipv6 nexthdr len for the reserved space. + * @_idsetup: callback to setup id and mask values. + * @_idlen: len for the next header id and mask, should be always the same. + * @_uncompress: callback for uncompression call. + * @_compress: callback for compression call. + */ +#define LOWPAN_NHC(__nhc, _name, _nexthdr, \ + _hdrlen, _idsetup, _idlen, \ + _uncompress, _compress) \ +static u8 __nhc##_val[_idlen]; \ +static u8 __nhc##_mask[_idlen]; \ +static struct lowpan_nhc __nhc = { \ + .name = _name, \ + .nexthdr = _nexthdr, \ + .nexthdrlen = _hdrlen, \ + .id = __nhc##_val, \ + .idmask = __nhc##_mask, \ + .idlen = _idlen, \ + .idsetup = _idsetup, \ + .uncompress = _uncompress, \ + .compress = _compress, \ +} + +#define module_lowpan_nhc(__nhc) \ +static int __init __nhc##_init(void) \ +{ \ + return lowpan_nhc_add(&(__nhc)); \ +} \ +module_init(__nhc##_init); \ +static void __exit __nhc##_exit(void) \ +{ \ + lowpan_nhc_del(&(__nhc)); \ +} \ +module_exit(__nhc##_exit); + +/** + * struct lowpan_nhc - hold 6lowpan next hdr compression ifnformation + * + * @node: holder for the rbtree. + * @name: name of the specific next header compression + * @nexthdr: next header value of the protocol which should be compressed. + * @nexthdrlen: ipv6 nexthdr len for the reserved space. + * @id: array for nhc id. Note this need to be in network byteorder. + * @mask: array for nhc id mask. Note this need to be in network byteorder. + * @len: the length of the next header id and mask. + * @setup: callback to setup fill the next header id value and mask. + * @compress: callback to do the header compression. + * @uncompress: callback to do the header uncompression. + */ +struct lowpan_nhc { + struct rb_node node; + const char *name; + const u8 nexthdr; + const size_t nexthdrlen; + u8 *id; + u8 *idmask; + const size_t idlen; + + void (*idsetup)(struct lowpan_nhc *nhc); + int (*uncompress)(struct sk_buff *skb, size_t needed); + int (*compress)(struct sk_buff *skb, u8 **hc_ptr); +}; + +/** + * lowpan_nhc_by_nexthdr - return the 6lowpan nhc by ipv6 nexthdr. + * + * @nexthdr: ipv6 nexthdr value. + */ +struct lowpan_nhc *lowpan_nhc_by_nexthdr(u8 nexthdr); + +/** + * lowpan_nhc_check_compression - checks if we support compression format. If + * we support the nhc by nexthdr field, the 6LoWPAN iphc NHC bit will be + * set. If we don't support nexthdr will be added as inline data to the + * 6LoWPAN header. + * + * @skb: skb of 6LoWPAN header to read nhc and replace header. + * @hdr: ipv6hdr to check the nexthdr value + * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of + * replaced header. + * @iphc0: iphc0 pointer to set the 6LoWPAN NHC bit + */ +int lowpan_nhc_check_compression(struct sk_buff *skb, + const struct ipv6hdr *hdr, u8 **hc_ptr, + u8 *iphc0); + +/** + * lowpan_nhc_do_compression - calling compress callback for nhc + * + * @skb: skb of 6LoWPAN header to read nhc and replace header. + * @hdr: ipv6hdr to set the nexthdr value + * @hc_ptr: pointer for 6LoWPAN header which should increment at the end of + * replaced header. + */ +int lowpan_nhc_do_compression(struct sk_buff *skb, const struct ipv6hdr *hdr, + u8 **hc_ptr); + +/** + * lowpan_nhc_do_uncompression - calling uncompress callback for nhc + * + * @nhc: 6LoWPAN nhc context, get by lowpan_nhc_by_ functions. + * @skb: skb of 6LoWPAN header, skb->data should be pointed to nhc id value. + * @dev: netdevice for print logging information. + * @hdr: ipv6hdr for setting nexthdr value. + */ +int lowpan_nhc_do_uncompression(struct sk_buff *skb, struct net_device *dev, + struct ipv6hdr *hdr); + +/** + * lowpan_nhc_add - register a next header compression to framework + * + * @nhc: nhc which should be add. + */ +int lowpan_nhc_add(struct lowpan_nhc *nhc); + +/** + * lowpan_nhc_del - delete a next header compression from framework + * + * @nhc: nhc which should be delete. + */ +void lowpan_nhc_del(struct lowpan_nhc *nhc); + +/** + * lowpan_nhc_init - adding all default nhcs + */ +void lowpan_nhc_init(void); + +#endif /* __6LOWPAN_NHC_H */ |
