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lowpan6: refactor decompression to not allocate a pbuf
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@ -886,31 +886,42 @@ lowpan6_output(struct netif *netif, struct pbuf *q, const ip6_addr_t *ip6addr)
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return lowpan6_frag(netif, q, &src, &dest);
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return lowpan6_frag(netif, q, &src, &dest);
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}
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}
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static struct pbuf *
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/** Decompress IPv6 and UDP headers compressed according to RFC 6282
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lowpan6_decompress(struct pbuf *p, struct ieee_802154_addr *src, struct ieee_802154_addr *dest)
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*
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* @param lowpan6_buffer compressed headers, first byte is the dispatch byte
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* @param lowpan6_bufsize size of lowpan6_buffer (may include data after headers)
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* @param decomp_buffer buffer where the decompressed headers are stored
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* @param decomp_bufsize size of decomp_buffer
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* @param hdr_size_comp returns the size of the compressed headers (skip to get to data)
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* @param hdr_size_decomp returns the size of the decompressed headers (IPv6 + UDP)
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* @param datagram_size datagram size from fragments or 0 if unfragmented
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* @param compressed_size compressed datagram size (for unfragmented rx)
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* @param src source address of the outer layer, used for address compression
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* @param dst destination address of the outer layer, used for address compression
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* @return ERR_OK if decompression succeeded, an error otherwise
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*/
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static err_t
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lowpan6_decompress_hdr(u8_t *lowpan6_buffer, size_t lowpan6_bufsize,
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u8_t *decomp_buffer, size_t decomp_bufsize,
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u16_t *hdr_size_comp, u16_t *hdr_size_decomp,
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u16_t datagram_size, u16_t compressed_size,
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struct ieee_802154_addr *src, struct ieee_802154_addr *dest)
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{
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{
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struct pbuf *q;
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u8_t *lowpan6_buffer;
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u16_t lowpan6_offset;
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u16_t lowpan6_offset;
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struct ip6_hdr *ip6hdr;
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struct ip6_hdr *ip6hdr;
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s8_t i;
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s8_t i;
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s8_t ip6_offset = IP6_HLEN;
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u16_t ip6_offset = IP6_HLEN;
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#if LWIP_UDP
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LWIP_ASSERT("lowpan6_buffer != NULL", lowpan6_buffer != NULL);
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#define UDP_HLEN_ALLOC UDP_HLEN
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LWIP_ASSERT("decomp_buffer != NULL", decomp_buffer != NULL);
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#else
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LWIP_ASSERT("src != NULL", src != NULL);
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#define UDP_HLEN_ALLOC 0
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LWIP_ASSERT("dest != NULL", dest != NULL);
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#endif
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q = pbuf_alloc(PBUF_IP, p->len + IP6_HLEN + UDP_HLEN_ALLOC, PBUF_POOL);
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ip6hdr = (struct ip6_hdr *)decomp_buffer;
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if (q == NULL) {
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if (decomp_bufsize < IP6_HLEN) {
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pbuf_free(p);
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return ERR_MEM;
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return NULL;
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}
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}
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lowpan6_buffer = (u8_t *)p->payload;
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ip6hdr = (struct ip6_hdr *)q->payload;
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lowpan6_offset = 2;
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lowpan6_offset = 2;
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if (lowpan6_buffer[1] & 0x80) {
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if (lowpan6_buffer[1] & 0x80) {
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lowpan6_offset++;
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lowpan6_offset++;
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@ -998,9 +1009,7 @@ lowpan6_decompress(struct pbuf *p, struct ieee_802154_addr *src, struct ieee_802
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}
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}
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if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
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if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
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/* Error */
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/* Error */
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pbuf_free(p);
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return ERR_VAL;
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pbuf_free(q);
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return NULL;
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}
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}
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#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
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#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
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ip6hdr->src.addr[0] = lowpan6_data.lowpan6_context[i].addr[0];
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ip6hdr->src.addr[0] = lowpan6_data.lowpan6_context[i].addr[0];
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@ -1031,9 +1040,7 @@ lowpan6_decompress(struct pbuf *p, struct ieee_802154_addr *src, struct ieee_802
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/* Multicast destination */
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/* Multicast destination */
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if (lowpan6_buffer[1] & 0x04) {
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if (lowpan6_buffer[1] & 0x04) {
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/* @todo support stateful multicast addressing */
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/* @todo support stateful multicast addressing */
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pbuf_free(p);
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return ERR_VAL;
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pbuf_free(q);
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return NULL;
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}
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}
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if ((lowpan6_buffer[1] & 0x03) == 0x00) {
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if ((lowpan6_buffer[1] & 0x03) == 0x00) {
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@ -1070,9 +1077,7 @@ lowpan6_decompress(struct pbuf *p, struct ieee_802154_addr *src, struct ieee_802
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}
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}
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if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
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if (i >= LWIP_6LOWPAN_NUM_CONTEXTS) {
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/* Error */
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/* Error */
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pbuf_free(p);
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return ERR_VAL;
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pbuf_free(q);
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return NULL;
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}
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}
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#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
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#if LWIP_6LOWPAN_NUM_CONTEXTS > 0
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ip6hdr->dest.addr[0] = lowpan6_data.lowpan6_context[i].addr[0];
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ip6hdr->dest.addr[0] = lowpan6_data.lowpan6_context[i].addr[0];
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@ -1115,13 +1120,14 @@ lowpan6_decompress(struct pbuf *p, struct ieee_802154_addr *src, struct ieee_802
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/* UDP compression */
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/* UDP compression */
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IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_UDP);
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IP6H_NEXTH_SET(ip6hdr, IP6_NEXTH_UDP);
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udphdr = (struct udp_hdr *)((u8_t *)q->payload + ip6_offset);
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udphdr = (struct udp_hdr *)((u8_t *)decomp_buffer + ip6_offset);
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if (decomp_bufsize < IP6_HLEN + UDP_HLEN) {
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return ERR_MEM;
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}
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if (lowpan6_buffer[lowpan6_offset] & 0x04) {
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if (lowpan6_buffer[lowpan6_offset] & 0x04) {
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/* @todo support checksum decompress */
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/* @todo support checksum decompress */
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pbuf_free(p);
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return ERR_VAL;
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pbuf_free(q);
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return NULL;
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}
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}
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/* Decompress ports */
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/* Decompress ports */
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@ -1146,33 +1152,96 @@ lowpan6_decompress(struct pbuf *p, struct ieee_802154_addr *src, struct ieee_802
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udphdr->chksum = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
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udphdr->chksum = lwip_htons(lowpan6_buffer[lowpan6_offset] << 8 | lowpan6_buffer[lowpan6_offset + 1]);
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lowpan6_offset += 2;
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lowpan6_offset += 2;
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udphdr->len = lwip_htons(p->tot_len - lowpan6_offset + UDP_HLEN);
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ip6_offset += UDP_HLEN;
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ip6_offset += UDP_HLEN;
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if (datagram_size == 0) {
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datagram_size = compressed_size - lowpan6_offset + ip6_offset;
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}
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udphdr->len = lwip_htons(datagram_size - IP6_HLEN);
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} else
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} else
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#endif /* LWIP_UDP */
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#endif /* LWIP_UDP */
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{
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{
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/* @todo support NHC other than UDP */
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/* @todo support NHC other than UDP */
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pbuf_free(p);
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return ERR_VAL;
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pbuf_free(q);
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return NULL;
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}
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}
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}
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}
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if (datagram_size == 0) {
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datagram_size = compressed_size - lowpan6_offset + ip6_offset;
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}
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/* Infer IPv6 payload length for header */
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IP6H_PLEN_SET(ip6hdr, datagram_size - IP6_HLEN);
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/* Now we copy leftover contents from p to q, so we have all L2 and L3 headers (and L4?) in a single PBUF.
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if (lowpan6_offset > lowpan6_bufsize) {
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* Replace p with q, and free p */
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/* input buffer overflow */
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return ERR_VAL;
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}
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if (hdr_size_comp) {
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*hdr_size_comp = lowpan6_offset;
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}
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if (hdr_size_decomp) {
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*hdr_size_decomp = ip6_offset;
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}
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return ERR_OK;
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}
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static struct pbuf *
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lowpan6_decompress(struct pbuf *p, u16_t datagram_size, struct ieee_802154_addr *src, struct ieee_802154_addr *dest)
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{
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struct pbuf *q;
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u16_t lowpan6_offset, ip6_offset;
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err_t err;
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#if LWIP_UDP
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#define UDP_HLEN_ALLOC UDP_HLEN
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#else
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#define UDP_HLEN_ALLOC 0
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#endif
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/* Allocate a buffer for decompression. This buffer will be too big and will be
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trimmed once the final size is known. */
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q = pbuf_alloc(PBUF_IP, p->len + IP6_HLEN + UDP_HLEN_ALLOC, PBUF_POOL);
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if (q == NULL) {
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pbuf_free(p);
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return NULL;
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}
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if (q->len < IP6_HLEN + UDP_HLEN_ALLOC) {
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/* The headers need to fit into the first pbuf */
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pbuf_free(p);
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pbuf_free(q);
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return NULL;
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}
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/* Decompress the IPv6 (and possibly UDP) header(s) into the new pbuf */
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err = lowpan6_decompress_hdr((u8_t *)p->payload, p->len, (u8_t *)q->payload, q->len,
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&lowpan6_offset, &ip6_offset, datagram_size, p->tot_len, src, dest);
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if (err != ERR_OK) {
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pbuf_free(p);
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pbuf_free(q);
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return NULL;
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}
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/* Now we copy leftover contents from p to q, so we have all L2 and L3 headers
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(and L4?) in a single pbuf: */
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/* Hide the compressed headers in p */
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pbuf_remove_header(p, lowpan6_offset);
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pbuf_remove_header(p, lowpan6_offset);
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MEMCPY((u8_t *)q->payload + ip6_offset, p->payload, p->len);
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/* Temporarily hide the headers in q... */
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q->len = q->tot_len = ip6_offset + p->len;
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pbuf_remove_header(q, ip6_offset);
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/* ... copy the rest of p into q... */
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pbuf_copy(q, p);
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/* ... and reveal the headers again... */
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pbuf_add_header_force(q, ip6_offset);
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/* ... trim the pbuf to its correct size... */
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pbuf_realloc(q, ip6_offset + p->len);
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/* ... and cat possibly remaining (data-only) pbufs */
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if (p->next != NULL) {
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if (p->next != NULL) {
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pbuf_cat(q, p->next);
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pbuf_cat(q, p->next);
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}
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}
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/* the original (first) pbuf can now be freed */
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p->next = NULL;
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p->next = NULL;
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pbuf_free(p);
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pbuf_free(p);
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/* Infer IPv6 payload length for header */
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IP6H_PLEN_SET(ip6hdr, q->tot_len - IP6_HLEN);
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/* all done */
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/* all done */
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return q;
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return q;
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}
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}
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@ -1187,7 +1256,8 @@ lowpan6_input(struct pbuf *p, struct netif *netif)
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u8_t *puc;
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u8_t *puc;
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s8_t i;
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s8_t i;
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struct ieee_802154_addr src, dest;
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struct ieee_802154_addr src, dest;
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u16_t datagram_size, datagram_offset, datagram_tag;
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u16_t datagram_size = 0;
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u16_t datagram_offset, datagram_tag;
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struct lowpan6_reass_helper *lrh, *lrh_temp;
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struct lowpan6_reass_helper *lrh, *lrh_temp;
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if (p == NULL) {
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if (p == NULL) {
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@ -1317,7 +1387,7 @@ lowpan6_input(struct pbuf *p, struct netif *netif)
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pbuf_remove_header(p, 1); /* hide dispatch byte. */
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pbuf_remove_header(p, 1); /* hide dispatch byte. */
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} else if ((*puc & 0xe0 ) == 0x60) {
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} else if ((*puc & 0xe0 ) == 0x60) {
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/* IPv6 headers are compressed using IPHC. */
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/* IPv6 headers are compressed using IPHC. */
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p = lowpan6_decompress(p, &src, &dest);
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p = lowpan6_decompress(p, 0, &src, &dest);
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if (p == NULL) {
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if (p == NULL) {
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MIB2_STATS_NETIF_INC(netif, ifindiscards);
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MIB2_STATS_NETIF_INC(netif, ifindiscards);
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return ERR_OK;
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return ERR_OK;
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