^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) // SPDX-License-Identifier: GPL-2.0-or-later
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) * 6LoWPAN IPv6 UDP compression according to RFC6282
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Authors:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) * Alexander Aring <aar@pengutronix.de>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Orignal written by:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) * Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * Jon Smirl <jonsmirl@gmail.com>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include "nhc.h"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) #define LOWPAN_NHC_UDP_MASK 0xF8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) #define LOWPAN_NHC_UDP_ID 0xF0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) #define LOWPAN_NHC_UDP_IDLEN 1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) #define LOWPAN_NHC_UDP_4BIT_PORT 0xF0B0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) #define LOWPAN_NHC_UDP_4BIT_MASK 0xFFF0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) #define LOWPAN_NHC_UDP_8BIT_PORT 0xF000
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) #define LOWPAN_NHC_UDP_8BIT_MASK 0xFF00
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) /* values for port compression, _with checksum_ ie bit 5 set to 0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) /* all inline */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #define LOWPAN_NHC_UDP_CS_P_00 0xF0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) /* source 16bit inline, dest = 0xF0 + 8 bit inline */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #define LOWPAN_NHC_UDP_CS_P_01 0xF1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) /* source = 0xF0 + 8bit inline, dest = 16 bit inline */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) #define LOWPAN_NHC_UDP_CS_P_10 0xF2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) /* source & dest = 0xF0B + 4bit inline */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) #define LOWPAN_NHC_UDP_CS_P_11 0xF3
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) /* checksum elided */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) #define LOWPAN_NHC_UDP_CS_C 0x04
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) static int udp_uncompress(struct sk_buff *skb, size_t needed)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) u8 tmp = 0, val = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) struct udphdr uh;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) bool fail;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) int err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) fail = lowpan_fetch_skb(skb, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) pr_debug("UDP header uncompression\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) switch (tmp & LOWPAN_NHC_UDP_CS_P_11) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) case LOWPAN_NHC_UDP_CS_P_00:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) fail |= lowpan_fetch_skb(skb, &uh.source, sizeof(uh.source));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) fail |= lowpan_fetch_skb(skb, &uh.dest, sizeof(uh.dest));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) case LOWPAN_NHC_UDP_CS_P_01:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) fail |= lowpan_fetch_skb(skb, &uh.source, sizeof(uh.source));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) uh.dest = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) case LOWPAN_NHC_UDP_CS_P_10:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) uh.source = htons(val + LOWPAN_NHC_UDP_8BIT_PORT);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) fail |= lowpan_fetch_skb(skb, &uh.dest, sizeof(uh.dest));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) case LOWPAN_NHC_UDP_CS_P_11:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) fail |= lowpan_fetch_skb(skb, &val, sizeof(val));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64) uh.source = htons(LOWPAN_NHC_UDP_4BIT_PORT + (val >> 4));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) uh.dest = htons(LOWPAN_NHC_UDP_4BIT_PORT + (val & 0x0f));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) BUG();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) pr_debug("uncompressed UDP ports: src = %d, dst = %d\n",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) ntohs(uh.source), ntohs(uh.dest));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) /* checksum */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) if (tmp & LOWPAN_NHC_UDP_CS_C) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) pr_debug_ratelimited("checksum elided currently not supported\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) fail = true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) fail |= lowpan_fetch_skb(skb, &uh.check, sizeof(uh.check));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) if (fail)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) return -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) /* UDP length needs to be infered from the lower layers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) * here, we obtain the hint from the remaining size of the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) * frame
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) switch (lowpan_dev(skb->dev)->lltype) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) case LOWPAN_LLTYPE_IEEE802154:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) if (lowpan_802154_cb(skb)->d_size)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) uh.len = htons(lowpan_802154_cb(skb)->d_size -
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) sizeof(struct ipv6hdr));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) uh.len = htons(skb->len + sizeof(struct udphdr));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) uh.len = htons(skb->len + sizeof(struct udphdr));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) pr_debug("uncompressed UDP length: src = %d", ntohs(uh.len));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) /* replace the compressed UDP head by the uncompressed UDP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) * header
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) err = skb_cow(skb, needed);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) if (unlikely(err))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) skb_push(skb, sizeof(struct udphdr));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) skb_copy_to_linear_data(skb, &uh, sizeof(struct udphdr));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) static int udp_compress(struct sk_buff *skb, u8 **hc_ptr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) const struct udphdr *uh = udp_hdr(skb);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) u8 tmp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) if (((ntohs(uh->source) & LOWPAN_NHC_UDP_4BIT_MASK) ==
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) LOWPAN_NHC_UDP_4BIT_PORT) &&
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) ((ntohs(uh->dest) & LOWPAN_NHC_UDP_4BIT_MASK) ==
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) LOWPAN_NHC_UDP_4BIT_PORT)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) pr_debug("UDP header: both ports compression to 4 bits\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) /* compression value */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) tmp = LOWPAN_NHC_UDP_CS_P_11;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) /* source and destination port */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_4BIT_PORT +
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) ((ntohs(uh->source) - LOWPAN_NHC_UDP_4BIT_PORT) << 4);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) } else if ((ntohs(uh->dest) & LOWPAN_NHC_UDP_8BIT_MASK) ==
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) LOWPAN_NHC_UDP_8BIT_PORT) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) pr_debug("UDP header: remove 8 bits of dest\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) /* compression value */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) tmp = LOWPAN_NHC_UDP_CS_P_01;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) /* source port */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) /* destination port */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) tmp = ntohs(uh->dest) - LOWPAN_NHC_UDP_8BIT_PORT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) } else if ((ntohs(uh->source) & LOWPAN_NHC_UDP_8BIT_MASK) ==
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) LOWPAN_NHC_UDP_8BIT_PORT) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) pr_debug("UDP header: remove 8 bits of source\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) /* compression value */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) tmp = LOWPAN_NHC_UDP_CS_P_10;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) /* source port */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) tmp = ntohs(uh->source) - LOWPAN_NHC_UDP_8BIT_PORT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) /* destination port */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) pr_debug("UDP header: can't compress\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) /* compression value */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) tmp = LOWPAN_NHC_UDP_CS_P_00;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) lowpan_push_hc_data(hc_ptr, &tmp, sizeof(tmp));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) /* source port */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) lowpan_push_hc_data(hc_ptr, &uh->source, sizeof(uh->source));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) /* destination port */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) lowpan_push_hc_data(hc_ptr, &uh->dest, sizeof(uh->dest));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) /* checksum is always inline */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) lowpan_push_hc_data(hc_ptr, &uh->check, sizeof(uh->check));
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) static void udp_nhid_setup(struct lowpan_nhc *nhc)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) nhc->id[0] = LOWPAN_NHC_UDP_ID;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) nhc->idmask[0] = LOWPAN_NHC_UDP_MASK;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) LOWPAN_NHC(nhc_udp, "RFC6282 UDP", NEXTHDR_UDP, sizeof(struct udphdr),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) udp_nhid_setup, LOWPAN_NHC_UDP_IDLEN, udp_uncompress, udp_compress);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) module_lowpan_nhc(nhc_udp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) MODULE_DESCRIPTION("6LoWPAN next header RFC6282 UDP compression");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) MODULE_LICENSE("GPL");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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