From 72a5e6bb5120d6464c9e7855c5a22555ede819dc Mon Sep 17 00:00:00 2001 From: Alexander Aring Date: Wed, 2 Sep 2015 14:21:25 +0200 Subject: [PATCH] ieee820154: 6lowpan: dispatch evaluation rework This patch complete reworks the evaluation of 6lowpan dispatch value by introducing a receive handler mechanism for each dispatch value. A list of changes: - Doing uncompression on-the-fly when FRAG1 is received, this require some special handling for 802.15.4 lltype in generic 6lowpan branch for setting the payload length correct. - Fix dispatch mask for fragmentation. - Add IPv6 dispatch evaluation for FRAG1. - Add skb_unshare for dispatch which might manipulate the skb data buffer. Cc: Jukka Rissanen Reviewed-by: Stefan Schmidt Signed-off-by: Alexander Aring Signed-off-by: Marcel Holtmann --- include/net/6lowpan.h | 31 ++++- net/6lowpan/iphc.c | 13 +- net/6lowpan/nhc_udp.c | 13 +- net/ieee802154/6lowpan/6lowpan_i.h | 12 ++ net/ieee802154/6lowpan/reassembly.c | 142 ++++++++++++++------- net/ieee802154/6lowpan/rx.c | 188 +++++++++++++++++++--------- 6 files changed, 288 insertions(+), 111 deletions(-) diff --git a/include/net/6lowpan.h b/include/net/6lowpan.h index a2f59ec98d24..35098411dbb4 100644 --- a/include/net/6lowpan.h +++ b/include/net/6lowpan.h @@ -126,13 +126,19 @@ (((a)[6]) == 0xFF) && \ (((a)[7]) == 0xFF)) -#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */ -#define LOWPAN_DISPATCH_HC1 0x42 /* 01000010 = 66 */ -#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */ -#define LOWPAN_DISPATCH_FRAG1 0xc0 /* 11000xxx */ -#define LOWPAN_DISPATCH_FRAGN 0xe0 /* 11100xxx */ +#define LOWPAN_DISPATCH_IPV6 0x41 /* 01000001 = 65 */ +#define LOWPAN_DISPATCH_IPHC 0x60 /* 011xxxxx = ... */ +#define LOWPAN_DISPATCH_IPHC_MASK 0xe0 -#define LOWPAN_DISPATCH_MASK 0xf8 /* 11111000 */ +static inline bool lowpan_is_ipv6(u8 dispatch) +{ + return dispatch == LOWPAN_DISPATCH_IPV6; +} + +static inline bool lowpan_is_iphc(u8 dispatch) +{ + return (dispatch & LOWPAN_DISPATCH_IPHC_MASK) == LOWPAN_DISPATCH_IPHC; +} #define LOWPAN_FRAG_TIMEOUT (HZ * 60) /* time-out 60 sec */ @@ -218,6 +224,19 @@ struct lowpan_priv *lowpan_priv(const struct net_device *dev) return netdev_priv(dev); } +struct lowpan_802154_cb { + u16 d_tag; + unsigned int d_size; + u8 d_offset; +}; + +static inline +struct lowpan_802154_cb *lowpan_802154_cb(const struct sk_buff *skb) +{ + BUILD_BUG_ON(sizeof(struct lowpan_802154_cb) > sizeof(skb->cb)); + return (struct lowpan_802154_cb *)skb->cb; +} + #ifdef DEBUG /* print data in line */ static inline void raw_dump_inline(const char *caller, char *msg, diff --git a/net/6lowpan/iphc.c b/net/6lowpan/iphc.c index 1e0071fdcf72..78c8a495b571 100644 --- a/net/6lowpan/iphc.c +++ b/net/6lowpan/iphc.c @@ -366,7 +366,18 @@ lowpan_header_decompress(struct sk_buff *skb, struct net_device *dev, return err; } - hdr.payload_len = htons(skb->len); + switch (lowpan_priv(dev)->lltype) { + case LOWPAN_LLTYPE_IEEE802154: + if (lowpan_802154_cb(skb)->d_size) + hdr.payload_len = htons(lowpan_802154_cb(skb)->d_size - + sizeof(struct ipv6hdr)); + else + hdr.payload_len = htons(skb->len); + break; + default: + hdr.payload_len = htons(skb->len); + break; + } pr_debug("skb headroom size = %d, data length = %d\n", skb_headroom(skb), skb->len); diff --git a/net/6lowpan/nhc_udp.c b/net/6lowpan/nhc_udp.c index c6bcaeb428ae..72d0b57eb6e5 100644 --- a/net/6lowpan/nhc_udp.c +++ b/net/6lowpan/nhc_udp.c @@ -71,7 +71,18 @@ static int udp_uncompress(struct sk_buff *skb, size_t needed) * here, we obtain the hint from the remaining size of the * frame */ - uh.len = htons(skb->len + sizeof(struct udphdr)); + switch (lowpan_priv(skb->dev)->lltype) { + case LOWPAN_LLTYPE_IEEE802154: + if (lowpan_802154_cb(skb)->d_size) + uh.len = htons(lowpan_802154_cb(skb)->d_size - + sizeof(struct ipv6hdr)); + else + uh.len = htons(skb->len + sizeof(struct udphdr)); + break; + default: + uh.len = htons(skb->len + sizeof(struct udphdr)); + break; + } pr_debug("uncompressed UDP length: src = %d", ntohs(uh.len)); /* replace the compressed UDP head by the uncompressed UDP diff --git a/net/ieee802154/6lowpan/6lowpan_i.h b/net/ieee802154/6lowpan/6lowpan_i.h index 9aa7b62b87fa..b4e17a7c0df0 100644 --- a/net/ieee802154/6lowpan/6lowpan_i.h +++ b/net/ieee802154/6lowpan/6lowpan_i.h @@ -7,6 +7,15 @@ #include #include +typedef unsigned __bitwise__ lowpan_rx_result; +#define RX_CONTINUE ((__force lowpan_rx_result) 0u) +#define RX_DROP_UNUSABLE ((__force lowpan_rx_result) 1u) +#define RX_DROP ((__force lowpan_rx_result) 2u) +#define RX_QUEUED ((__force lowpan_rx_result) 3u) + +#define LOWPAN_DISPATCH_FRAG1 0xc0 +#define LOWPAN_DISPATCH_FRAGN 0xe0 + struct lowpan_create_arg { u16 tag; u16 d_size; @@ -62,4 +71,7 @@ int lowpan_header_create(struct sk_buff *skb, struct net_device *dev, const void *_saddr, unsigned int len); netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct net_device *dev); +int lowpan_iphc_decompress(struct sk_buff *skb); +lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb); + #endif /* __IEEE802154_6LOWPAN_I_H__ */ diff --git a/net/ieee802154/6lowpan/reassembly.c b/net/ieee802154/6lowpan/reassembly.c index 0fc3350ace5a..12e8cf4bda9f 100644 --- a/net/ieee802154/6lowpan/reassembly.c +++ b/net/ieee802154/6lowpan/reassembly.c @@ -32,17 +32,6 @@ static const char lowpan_frags_cache_name[] = "lowpan-frags"; -struct lowpan_frag_info { - u16 d_tag; - u16 d_size; - u8 d_offset; -}; - -static struct lowpan_frag_info *lowpan_cb(struct sk_buff *skb) -{ - return (struct lowpan_frag_info *)skb->cb; -} - static struct inet_frags lowpan_frags; static int lowpan_frag_reasm(struct lowpan_frag_queue *fq, @@ -111,7 +100,7 @@ out: } static inline struct lowpan_frag_queue * -fq_find(struct net *net, const struct lowpan_frag_info *frag_info, +fq_find(struct net *net, const struct lowpan_802154_cb *cb, const struct ieee802154_addr *src, const struct ieee802154_addr *dst) { @@ -121,12 +110,12 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info, struct netns_ieee802154_lowpan *ieee802154_lowpan = net_ieee802154_lowpan(net); - arg.tag = frag_info->d_tag; - arg.d_size = frag_info->d_size; + arg.tag = cb->d_tag; + arg.d_size = cb->d_size; arg.src = src; arg.dst = dst; - hash = lowpan_hash_frag(frag_info->d_tag, frag_info->d_size, src, dst); + hash = lowpan_hash_frag(cb->d_tag, cb->d_size, src, dst); q = inet_frag_find(&ieee802154_lowpan->frags, &lowpan_frags, &arg, hash); @@ -138,7 +127,7 @@ fq_find(struct net *net, const struct lowpan_frag_info *frag_info, } static int lowpan_frag_queue(struct lowpan_frag_queue *fq, - struct sk_buff *skb, const u8 frag_type) + struct sk_buff *skb, u8 frag_type) { struct sk_buff *prev, *next; struct net_device *ldev; @@ -147,8 +136,8 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq, if (fq->q.flags & INET_FRAG_COMPLETE) goto err; - offset = lowpan_cb(skb)->d_offset << 3; - end = lowpan_cb(skb)->d_size; + 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) { @@ -174,13 +163,16 @@ static int lowpan_frag_queue(struct lowpan_frag_queue *fq, * this fragment, right? */ prev = fq->q.fragments_tail; - if (!prev || lowpan_cb(prev)->d_offset < lowpan_cb(skb)->d_offset) { + 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_cb(next)->d_offset >= lowpan_cb(skb)->d_offset) + if (lowpan_802154_cb(next)->d_offset >= + lowpan_802154_cb(skb)->d_offset) break; /* bingo! */ prev = next; } @@ -200,13 +192,10 @@ found: skb->dev = NULL; fq->q.stamp = skb->tstamp; - if (frag_type == LOWPAN_DISPATCH_FRAG1) { - /* Calculate uncomp. 6lowpan header to estimate full size */ - fq->q.meat += lowpan_uncompress_size(skb, NULL); + if (frag_type == LOWPAN_DISPATCH_FRAG1) fq->q.flags |= INET_FRAG_FIRST_IN; - } else { - fq->q.meat += skb->len; - } + + 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) && @@ -325,24 +314,87 @@ out_oom: return -1; } -static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type, - struct lowpan_frag_info *frag_info) +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; + } +} + +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; +} + +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 +} + +#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 pattern = 0, low = 0; + u8 high = 0, low = 0; __be16 d_tag = 0; - fail = lowpan_fetch_skb(skb, &pattern, 1); + fail = lowpan_fetch_skb(skb, &high, 1); fail |= lowpan_fetch_skb(skb, &low, 1); - frag_info->d_size = (pattern & 7) << 8 | low; + /* 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); - frag_info->d_tag = ntohs(d_tag); + cb->d_tag = ntohs(d_tag); if (frag_type == LOWPAN_DISPATCH_FRAGN) { - fail |= lowpan_fetch_skb(skb, &frag_info->d_offset, 1); + fail |= lowpan_fetch_skb(skb, &cb->d_offset, 1); } else { skb_reset_network_header(skb); - frag_info->d_offset = 0; + 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)) @@ -351,27 +403,33 @@ static int lowpan_get_frag_info(struct sk_buff *skb, const u8 frag_type, return 0; } -int lowpan_frag_rcv(struct sk_buff *skb, const u8 frag_type) +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_frag_info *frag_info = lowpan_cb(skb); - struct ieee802154_addr source, dest; + struct lowpan_802154_cb *cb = lowpan_802154_cb(skb); + struct ieee802154_hdr hdr; int err; - source = mac_cb(skb)->source; - dest = mac_cb(skb)->dest; + if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0) + goto err; - err = lowpan_get_frag_info(skb, frag_type, frag_info); + err = lowpan_get_cb(skb, frag_type, cb); if (err < 0) goto err; - if (frag_info->d_size > IPV6_MIN_MTU) { + 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, frag_info, &source, &dest); + fq = fq_find(net, cb, &hdr.source, &hdr.dest); if (fq != NULL) { int ret; diff --git a/net/ieee802154/6lowpan/rx.c b/net/ieee802154/6lowpan/rx.c index f9cb70b6749f..fded1099fae0 100644 --- a/net/ieee802154/6lowpan/rx.c +++ b/net/ieee802154/6lowpan/rx.c @@ -15,8 +15,9 @@ #include "6lowpan_i.h" -static int lowpan_give_skb_to_device(struct sk_buff *skb, - struct net_device *wdev) +#define LOWPAN_DISPATCH_FRAG_MASK 0xf8 + +static int lowpan_give_skb_to_device(struct sk_buff *skb) { skb->protocol = htons(ETH_P_IPV6); skb->pkt_type = PACKET_HOST; @@ -24,21 +25,77 @@ static int lowpan_give_skb_to_device(struct sk_buff *skb, return netif_rx(skb); } -static int -iphc_decompress(struct sk_buff *skb, const struct ieee802154_hdr *hdr) +static int lowpan_rx_handlers_result(struct sk_buff *skb, lowpan_rx_result res) +{ + switch (res) { + case RX_CONTINUE: + /* nobody cared about this packet */ + net_warn_ratelimited("%s: received unknown dispatch\n", + __func__); + + /* fall-through */ + case RX_DROP_UNUSABLE: + kfree_skb(skb); + + /* fall-through */ + case RX_DROP: + return NET_RX_DROP; + case RX_QUEUED: + return lowpan_give_skb_to_device(skb); + default: + break; + } + + return NET_RX_DROP; +} + +static inline bool lowpan_is_frag1(u8 dispatch) +{ + return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAG1; +} + +static inline bool lowpan_is_fragn(u8 dispatch) +{ + return (dispatch & LOWPAN_DISPATCH_FRAG_MASK) == LOWPAN_DISPATCH_FRAGN; +} + +static lowpan_rx_result lowpan_rx_h_frag(struct sk_buff *skb) +{ + int ret; + + if (!(lowpan_is_frag1(*skb_network_header(skb)) || + lowpan_is_fragn(*skb_network_header(skb)))) + return RX_CONTINUE; + + ret = lowpan_frag_rcv(skb, *skb_network_header(skb) & + LOWPAN_DISPATCH_FRAG_MASK); + if (ret == 1) + return RX_QUEUED; + + /* Packet is freed by lowpan_frag_rcv on error or put into the frag + * bucket. + */ + return RX_DROP; +} + +int lowpan_iphc_decompress(struct sk_buff *skb) { - u8 iphc0, iphc1; struct ieee802154_addr_sa sa, da; + struct ieee802154_hdr hdr; + u8 iphc0, iphc1; void *sap, *dap; + if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0) + return -EINVAL; + raw_dump_table(__func__, "raw skb data dump", skb->data, skb->len); if (lowpan_fetch_skb_u8(skb, &iphc0) || lowpan_fetch_skb_u8(skb, &iphc1)) return -EINVAL; - ieee802154_addr_to_sa(&sa, &hdr->source); - ieee802154_addr_to_sa(&da, &hdr->dest); + ieee802154_addr_to_sa(&sa, &hdr.source); + ieee802154_addr_to_sa(&da, &hdr.dest); if (sa.addr_type == IEEE802154_ADDR_SHORT) sap = &sa.short_addr; @@ -55,78 +112,87 @@ iphc_decompress(struct sk_buff *skb, const struct ieee802154_hdr *hdr) IEEE802154_ADDR_LEN, iphc0, iphc1); } +static lowpan_rx_result lowpan_rx_h_iphc(struct sk_buff *skb) +{ + int ret; + + if (!lowpan_is_iphc(*skb_network_header(skb))) + return RX_CONTINUE; + + /* Setting datagram_offset to zero indicates non frag handling + * while doing lowpan_header_decompress. + */ + lowpan_802154_cb(skb)->d_size = 0; + + ret = lowpan_iphc_decompress(skb); + if (ret < 0) + return RX_DROP_UNUSABLE; + + return RX_QUEUED; +} + +lowpan_rx_result lowpan_rx_h_ipv6(struct sk_buff *skb) +{ + if (!lowpan_is_ipv6(*skb_network_header(skb))) + return RX_CONTINUE; + + /* Pull off the 1-byte of 6lowpan header. */ + skb_pull(skb, 1); + return RX_QUEUED; +} + +static int lowpan_invoke_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_rx_h_iphc); + CALL_RXH(lowpan_rx_h_frag); + CALL_RXH(lowpan_rx_h_ipv6); + +rxh_next: + return lowpan_rx_handlers_result(skb, res); +#undef CALL_RXH +} + static int lowpan_rcv(struct sk_buff *skb, struct net_device *wdev, struct packet_type *pt, struct net_device *orig_wdev) { - struct ieee802154_hdr hdr; struct net_device *ldev; - int ret; if (wdev->type != ARPHRD_IEEE802154 || skb->pkt_type == PACKET_OTHERHOST) - goto drop; + return NET_RX_DROP; ldev = wdev->ieee802154_ptr->lowpan_dev; if (!ldev || !netif_running(ldev)) - goto drop; + return NET_RX_DROP; /* Replacing skb->dev and followed rx handlers will manipulate skb. */ skb = skb_share_check(skb, GFP_ATOMIC); if (!skb) - goto drop; + return NET_RX_DROP; skb->dev = ldev; - if (ieee802154_hdr_peek_addrs(skb, &hdr) < 0) - goto drop_skb; - - /* check that it's our buffer */ - if (skb->data[0] == LOWPAN_DISPATCH_IPV6) { - /* Pull off the 1-byte of 6lowpan header. */ - skb_pull(skb, 1); - return lowpan_give_skb_to_device(skb, wdev); - } else { - switch (skb->data[0] & 0xe0) { - case LOWPAN_DISPATCH_IPHC: /* ipv6 datagram */ - ret = iphc_decompress(skb, &hdr); - if (ret < 0) - goto drop_skb; - - return lowpan_give_skb_to_device(skb, wdev); - case LOWPAN_DISPATCH_FRAG1: /* first fragment header */ - ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAG1); - if (ret == 1) { - ret = iphc_decompress(skb, &hdr); - if (ret < 0) - goto drop_skb; - - return lowpan_give_skb_to_device(skb, wdev); - } else if (ret == -1) { - return NET_RX_DROP; - } else { - return NET_RX_SUCCESS; - } - case LOWPAN_DISPATCH_FRAGN: /* next fragments headers */ - ret = lowpan_frag_rcv(skb, LOWPAN_DISPATCH_FRAGN); - if (ret == 1) { - ret = iphc_decompress(skb, &hdr); - if (ret < 0) - goto drop_skb; - - return lowpan_give_skb_to_device(skb, wdev); - } else if (ret == -1) { - return NET_RX_DROP; - } else { - return NET_RX_SUCCESS; - } - default: - break; - } + /* When receive frag1 it's likely that we manipulate the buffer. + * When recevie iphc we manipulate the data buffer. So we need + * to unshare the buffer. + */ + if (lowpan_is_frag1(*skb_network_header(skb)) || + lowpan_is_iphc(*skb_network_header(skb))) { + skb = skb_unshare(skb, GFP_ATOMIC); + if (!skb) + return RX_DROP; } -drop_skb: - kfree_skb(skb); -drop: - return NET_RX_DROP; + return lowpan_invoke_rx_handlers(skb); } static struct packet_type lowpan_packet_type = { -- 2.30.2