1 /* $NetBSD: in_offload.c,v 1.15 2024/07/05 04:31:54 rin Exp $ */ 2 3 /* 4 * Copyright (c)2005, 2006 YAMAMOTO Takashi, 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __KERNEL_RCSID(0, "$NetBSD: in_offload.c,v 1.15 2024/07/05 04:31:54 rin Exp $"); 31 32 #include <sys/param.h> 33 #include <sys/mbuf.h> 34 35 #include <net/if.h> 36 37 #include <netinet/in.h> 38 #include <netinet/in_systm.h> 39 #include <netinet/ip.h> 40 #include <netinet/ip_var.h> 41 #include <netinet/tcp.h> 42 #include <netinet/in_offload.h> 43 44 /* 45 * Handle M_CSUM_TSOv4 in software. Split the TCP payload in chunks of 46 * size MSS, and return mbuf chain consists of them. 47 */ 48 struct mbuf * 49 tcp4_segment(struct mbuf *m, int off) 50 { 51 int mss; 52 int iphlen, thlen; 53 int hlen, len; 54 struct ip *ip; 55 struct tcphdr *th; 56 uint16_t ipid, phsum; 57 uint32_t tcpseq; 58 struct mbuf *hdr = NULL; 59 struct mbuf *m0 = NULL; 60 struct mbuf *prev = NULL; 61 struct mbuf *n, *t; 62 int nsegs; 63 64 KASSERT((m->m_flags & M_PKTHDR) != 0); 65 KASSERT((m->m_pkthdr.csum_flags & M_CSUM_TSOv4) != 0); 66 67 m->m_pkthdr.csum_flags = 0; 68 69 len = m->m_pkthdr.len; 70 KASSERT(len >= off + sizeof(*ip) + sizeof(*th)); 71 72 hlen = off + sizeof(*ip); 73 if (m->m_len < hlen) { 74 m = m_pullup(m, hlen); 75 if (m == NULL) 76 goto quit; 77 } 78 ip = (void *)(mtod(m, char *) + off); 79 iphlen = ip->ip_hl * 4; 80 KASSERT(ip->ip_v == IPVERSION); 81 KASSERT(iphlen >= sizeof(*ip)); 82 KASSERT(ip->ip_p == IPPROTO_TCP); 83 ipid = ntohs(ip->ip_id); 84 85 hlen = off + iphlen + sizeof(*th); 86 if (m->m_len < hlen) { 87 m = m_pullup(m, hlen); 88 if (m == NULL) 89 goto quit; 90 } 91 th = (void *)(mtod(m, char *) + off + iphlen); 92 tcpseq = ntohl(th->th_seq); 93 thlen = th->th_off * 4; 94 hlen = off + iphlen + thlen; 95 96 mss = m->m_pkthdr.segsz; 97 KASSERT(mss != 0); 98 KASSERT(len > hlen); 99 100 t = m_split(m, hlen, M_NOWAIT); 101 if (t == NULL) 102 goto quit; 103 hdr = m; 104 m = t; 105 106 len -= hlen; 107 KASSERT(len % mss == 0); 108 109 ip = (void *)(mtod(hdr, char *) + off); 110 ip->ip_len = htons(iphlen + thlen + mss); 111 phsum = in_cksum_phdr(ip->ip_src.s_addr, ip->ip_dst.s_addr, 112 htons((uint16_t)(thlen + mss) + IPPROTO_TCP)); 113 114 for (nsegs = len / mss; nsegs > 0; nsegs--) { 115 if (nsegs > 1) { 116 n = m_dup(hdr, 0, hlen, M_NOWAIT); 117 if (n == NULL) 118 goto quit; 119 } else 120 n = hdr; 121 KASSERT(n->m_len == hlen); /* XXX */ 122 123 if (nsegs > 1) { 124 t = m_split(m, mss, M_NOWAIT); 125 if (t == NULL) { 126 m_freem(n); 127 goto quit; 128 } 129 } else 130 t = m; 131 m_cat(n, m); 132 m = t; 133 134 KASSERT(n->m_len >= hlen); /* XXX */ 135 136 if (m0 == NULL) 137 m0 = n; 138 139 if (prev != NULL) 140 prev->m_nextpkt = n; 141 142 n->m_pkthdr.len = hlen + mss; 143 n->m_nextpkt = NULL; /* XXX */ 144 145 ip = (void *)(mtod(n, char *) + off); 146 ip->ip_id = htons(ipid); 147 ip->ip_sum = 0; 148 ip->ip_sum = in4_cksum(n, 0, off, iphlen); 149 150 th = (void *)(mtod(n, char *) + off + iphlen); 151 th->th_seq = htonl(tcpseq); 152 th->th_sum = phsum; 153 th->th_sum = in4_cksum(n, 0, off + iphlen, thlen + mss); 154 155 tcpseq += mss; 156 ipid++; 157 prev = n; 158 } 159 return m0; 160 161 quit: 162 m_freem(hdr); 163 m_freem(m); 164 for (m = m0; m != NULL; m = n) { 165 n = m->m_nextpkt; 166 m_freem(m); 167 } 168 169 return NULL; 170 } 171 172 int 173 ip_tso_output(struct ifnet *ifp, struct mbuf *m, const struct sockaddr *sa, 174 struct rtentry *rt) 175 { 176 struct mbuf *n; 177 int error = 0; 178 179 m = tcp4_segment(m, 0); 180 if (m == NULL) 181 return ENOMEM; 182 do { 183 n = m->m_nextpkt; 184 if (error == 0) 185 error = ip_if_output(ifp, m, sa, rt); 186 else 187 m_freem(m); 188 m = n; 189 } while (m != NULL); 190 return error; 191 } 192 193 /* 194 * Compute now in software the IP and TCP/UDP checksums. Cancel the 195 * hardware offloading. 196 */ 197 void 198 in_undefer_cksum(struct mbuf *mh, size_t hdrlen, int csum_flags) 199 { 200 const size_t iphdrlen = M_CSUM_DATA_IPv4_IPHL(mh->m_pkthdr.csum_data); 201 uint16_t csum; 202 uint16_t ip_len; 203 uint16_t *csump; 204 struct mbuf *m = mh; 205 206 KASSERT(mh->m_flags & M_PKTHDR); 207 KASSERT(mh->m_pkthdr.len > hdrlen); 208 KASSERT((mh->m_pkthdr.csum_flags & csum_flags) == csum_flags); 209 210 /* 211 * Deal with prepended frame header as done by e.g. ether_output(). 212 * If first mbuf in chain has just the header, use second mbuf 213 * for the actual checksum. in4_csum() expects the passed mbuf 214 * to have the whole (struct ip) area contiguous. 215 */ 216 if (m->m_len <= hdrlen) { 217 hdrlen -= m->m_len; 218 m = m->m_next; 219 KASSERT(m != NULL); 220 } 221 222 if (__predict_true(hdrlen + sizeof(struct ip) <= m->m_len)) { 223 struct ip *ip = (struct ip *)(mtod(m, uint8_t *) + hdrlen); 224 225 ip_len = ip->ip_len; 226 csump = &ip->ip_sum; 227 } else { 228 const size_t ip_len_offset = 229 hdrlen + offsetof(struct ip, ip_len); 230 231 m_copydata(m, ip_len_offset, sizeof(ip_len), &ip_len); 232 csump = NULL; 233 } 234 ip_len = ntohs(ip_len); 235 236 if (csum_flags & M_CSUM_IPv4) { 237 csum = in4_cksum(m, 0, hdrlen, iphdrlen); 238 if (csump != NULL) { 239 *csump = csum; 240 } else { 241 const size_t offset = hdrlen + 242 offsetof(struct ip, ip_sum); 243 244 m_copyback(m, offset, sizeof(uint16_t), &csum); 245 } 246 } 247 248 if (csum_flags & (M_CSUM_UDPv4|M_CSUM_TCPv4)) { 249 size_t l4offset = hdrlen + iphdrlen; 250 251 csum = in4_cksum(m, 0, l4offset, ip_len - iphdrlen); 252 if (csum == 0 && (csum_flags & M_CSUM_UDPv4) != 0) 253 csum = 0xffff; 254 255 l4offset += M_CSUM_DATA_IPv4_OFFSET(m->m_pkthdr.csum_data); 256 257 if (__predict_true(l4offset + sizeof(uint16_t) <= m->m_len)) { 258 *(uint16_t *)(mtod(m, char *) + l4offset) = csum; 259 } else { 260 m_copyback(m, l4offset, sizeof(csum), (void *)&csum); 261 } 262 } 263 264 mh->m_pkthdr.csum_flags ^= csum_flags; 265 } 266 267 /* 268 * Compute now in software the TCP/UDP checksum. Cancel the hardware 269 * offloading. 270 */ 271 void 272 in_undefer_cksum_tcpudp(struct mbuf *m) 273 { 274 struct ip *ip; 275 uint16_t csum, offset; 276 277 KASSERT((m->m_flags & M_PKTHDR) != 0); 278 KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_TCPv4|M_CSUM_UDPv4)) != 0); 279 KASSERT((m->m_pkthdr.csum_flags & (M_CSUM_TCPv6|M_CSUM_UDPv6)) == 0); 280 281 ip = mtod(m, struct ip *); 282 offset = ip->ip_hl << 2; 283 284 csum = in4_cksum(m, 0, offset, ntohs(ip->ip_len) - offset); 285 if (csum == 0 && (m->m_pkthdr.csum_flags & M_CSUM_UDPv4) != 0) 286 csum = 0xffff; 287 288 offset += M_CSUM_DATA_IPv4_OFFSET(m->m_pkthdr.csum_data); 289 290 if ((offset + sizeof(uint16_t)) <= m->m_len) { 291 *(uint16_t *)(mtod(m, char *) + offset) = csum; 292 } else { 293 m_copyback(m, offset, sizeof(csum), (void *)&csum); 294 } 295 } 296
Indexes created Sat Sep 20 22:09:52 GMT 2025