1 /*- 2 * Copyright (c) 2020-2022 The FreeBSD Foundation 3 * Copyright (c) 2021-2022 Bjoern A. Zeeb 4 * 5 * This software was developed by Björn Zeeb under sponsorship from 6 * the FreeBSD Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 /* 31 * NOTE: this socket buffer compatibility code is highly EXPERIMENTAL. 32 * Do not rely on the internals of this implementation. They are highly 33 * likely to change as we will improve the integration to FreeBSD mbufs. 34 */ 35 36 #include <sys/cdefs.h> 37 #include "opt_ddb.h" 38 39 #include <sys/param.h> 40 #include <sys/types.h> 41 #include <sys/kernel.h> 42 #include <sys/malloc.h> 43 #include <sys/sysctl.h> 44 45 #ifdef DDB 46 #include <ddb/ddb.h> 47 #endif 48 49 #include <linux/skbuff.h> 50 #include <linux/slab.h> 51 #include <linux/gfp.h> 52 #ifdef __LP64__ 53 #include <linux/log2.h> 54 #endif 55 56 SYSCTL_DECL(_compat_linuxkpi); 57 SYSCTL_NODE(_compat_linuxkpi, OID_AUTO, skb, CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 58 "LinuxKPI skbuff"); 59 60 #ifdef SKB_DEBUG 61 int linuxkpi_debug_skb; 62 SYSCTL_INT(_compat_linuxkpi_skb, OID_AUTO, debug, CTLFLAG_RWTUN, 63 &linuxkpi_debug_skb, 0, "SKB debug level"); 64 #endif 65 66 #ifdef __LP64__ 67 /* 68 * Realtek wireless drivers (e.g., rtw88) require 32bit DMA in a single segment. 69 * busdma(9) has a hard time providing this currently for 3-ish pages at large 70 * quantities (see lkpi_pci_nseg1_fail in linux_pci.c). 71 * Work around this for now by allowing a tunable to enforce physical addresses 72 * allocation limits on 64bit platforms using "old-school" contigmalloc(9) to 73 * avoid bouncing. 74 */ 75 static int linuxkpi_skb_memlimit; 76 SYSCTL_INT(_compat_linuxkpi_skb, OID_AUTO, mem_limit, CTLFLAG_RDTUN, 77 &linuxkpi_skb_memlimit, 0, "SKB memory limit: 0=no limit, " 78 "1=32bit, 2=36bit, other=undef (currently 32bit)"); 79 #endif 80 81 static MALLOC_DEFINE(M_LKPISKB, "lkpiskb", "Linux KPI skbuff compat"); 82 83 struct sk_buff * 84 linuxkpi_alloc_skb(size_t size, gfp_t gfp) 85 { 86 struct sk_buff *skb; 87 size_t len; 88 89 len = sizeof(*skb) + size + sizeof(struct skb_shared_info); 90 /* 91 * Using our own type here not backing my kmalloc. 92 * We assume no one calls kfree directly on the skb. 93 */ 94 #ifdef __LP64__ 95 if (__predict_true(linuxkpi_skb_memlimit == 0)) { 96 skb = malloc(len, M_LKPISKB, linux_check_m_flags(gfp) | M_ZERO); 97 } else { 98 vm_paddr_t high; 99 100 switch (linuxkpi_skb_memlimit) { 101 case 2: 102 high = (0xfffffffff); /* 1<<36 really. */ 103 break; 104 case 1: 105 default: 106 high = (0xffffffff); /* 1<<32 really. */ 107 break; 108 } 109 len = roundup_pow_of_two(len); 110 skb = contigmalloc(len, M_LKPISKB, 111 linux_check_m_flags(gfp) | M_ZERO, 0, high, PAGE_SIZE, 0); 112 } 113 #else 114 skb = malloc(len, M_LKPISKB, linux_check_m_flags(gfp) | M_ZERO); 115 #endif 116 if (skb == NULL) 117 return (skb); 118 skb->_alloc_len = len; 119 skb->truesize = size; 120 121 skb->head = skb->data = skb->tail = (uint8_t *)(skb+1); 122 skb->end = skb->head + size; 123 124 skb->prev = skb->next = skb; 125 126 skb->shinfo = (struct skb_shared_info *)(skb->end); 127 128 SKB_TRACE_FMT(skb, "data %p size %zu", (skb) ? skb->data : NULL, size); 129 return (skb); 130 } 131 132 struct sk_buff * 133 linuxkpi_dev_alloc_skb(size_t size, gfp_t gfp) 134 { 135 struct sk_buff *skb; 136 size_t len; 137 138 len = size + NET_SKB_PAD; 139 skb = linuxkpi_alloc_skb(len, gfp); 140 141 if (skb != NULL) 142 skb_reserve(skb, NET_SKB_PAD); 143 144 SKB_TRACE_FMT(skb, "data %p size %zu len %zu", 145 (skb) ? skb->data : NULL, size, len); 146 return (skb); 147 } 148 149 struct sk_buff * 150 linuxkpi_build_skb(void *data, size_t fragsz) 151 { 152 struct sk_buff *skb; 153 154 if (data == NULL || fragsz == 0) 155 return (NULL); 156 157 /* Just allocate a skb without data area. */ 158 skb = linuxkpi_alloc_skb(0, GFP_KERNEL); 159 if (skb == NULL) 160 return (NULL); 161 162 skb->_flags |= _SKB_FLAGS_SKBEXTFRAG; 163 skb->truesize = fragsz; 164 skb->head = skb->data = data; 165 skb_reset_tail_pointer(skb); /* XXX is that correct? */ 166 skb->end = (void *)((uintptr_t)skb->head + fragsz); 167 168 return (skb); 169 } 170 171 struct sk_buff * 172 linuxkpi_skb_copy(struct sk_buff *skb, gfp_t gfp) 173 { 174 struct sk_buff *new; 175 struct skb_shared_info *shinfo; 176 size_t len; 177 unsigned int headroom; 178 179 /* Full buffer size + any fragments. */ 180 len = skb->end - skb->head + skb->data_len; 181 182 new = linuxkpi_alloc_skb(len, gfp); 183 if (new == NULL) 184 return (NULL); 185 186 headroom = skb_headroom(skb); 187 /* Fixup head and end. */ 188 skb_reserve(new, headroom); /* data and tail move headroom forward. */ 189 skb_put(new, skb->len); /* tail and len get adjusted */ 190 191 /* Copy data. */ 192 memcpy(new->head, skb->data - headroom, headroom + skb->len); 193 194 /* Deal with fragments. */ 195 shinfo = skb->shinfo; 196 if (shinfo->nr_frags > 0) { 197 printf("%s:%d: NOT YET SUPPORTED; missing %d frags\n", 198 __func__, __LINE__, shinfo->nr_frags); 199 SKB_TODO(); 200 } 201 202 /* Deal with header fields. */ 203 memcpy(new->cb, skb->cb, sizeof(skb->cb)); 204 SKB_IMPROVE("more header fields to copy?"); 205 206 return (new); 207 } 208 209 void 210 linuxkpi_kfree_skb(struct sk_buff *skb) 211 { 212 struct skb_shared_info *shinfo; 213 uint16_t fragno, count; 214 215 SKB_TRACE(skb); 216 if (skb == NULL) 217 return; 218 219 /* 220 * XXX TODO this will go away once we have skb backed by mbuf. 221 * currently we allow the mbuf to stay around and use a private 222 * free function to allow secondary resources to be freed along. 223 */ 224 if (skb->m != NULL) { 225 void *m; 226 227 m = skb->m; 228 skb->m = NULL; 229 230 KASSERT(skb->m_free_func != NULL, ("%s: skb %p has m %p but no " 231 "m_free_func %p\n", __func__, skb, m, skb->m_free_func)); 232 skb->m_free_func(m); 233 } 234 KASSERT(skb->m == NULL, 235 ("%s: skb %p m %p != NULL\n", __func__, skb, skb->m)); 236 237 shinfo = skb->shinfo; 238 for (count = fragno = 0; 239 count < shinfo->nr_frags && fragno < nitems(shinfo->frags); 240 fragno++) { 241 242 if (shinfo->frags[fragno].page != NULL) { 243 struct page *p; 244 245 p = shinfo->frags[fragno].page; 246 shinfo->frags[fragno].size = 0; 247 shinfo->frags[fragno].offset = 0; 248 shinfo->frags[fragno].page = NULL; 249 __free_page(p); 250 count++; 251 } 252 } 253 254 if ((skb->_flags & _SKB_FLAGS_SKBEXTFRAG) != 0) { 255 void *p; 256 257 p = skb->head; 258 skb_free_frag(p); 259 } 260 261 #ifdef __LP64__ 262 if (__predict_true(linuxkpi_skb_memlimit == 0)) 263 free(skb, M_LKPISKB); 264 else 265 contigfree(skb, skb->_alloc_len, M_LKPISKB); 266 #else 267 free(skb, M_LKPISKB); 268 #endif 269 } 270 271 #ifdef DDB 272 DB_SHOW_COMMAND(skb, db_show_skb) 273 { 274 struct sk_buff *skb; 275 int i; 276 277 if (!have_addr) { 278 db_printf("usage: show skb <addr>\n"); 279 return; 280 } 281 282 skb = (struct sk_buff *)addr; 283 284 db_printf("skb %p\n", skb); 285 db_printf("\tnext %p prev %p\n", skb->next, skb->prev); 286 db_printf("\tlist %p\n", &skb->list); 287 db_printf("\t_alloc_len %u len %u data_len %u truesize %u mac_len %u\n", 288 skb->_alloc_len, skb->len, skb->data_len, skb->truesize, 289 skb->mac_len); 290 db_printf("\tcsum %#06x l3hdroff %u l4hdroff %u priority %u qmap %u\n", 291 skb->csum, skb->l3hdroff, skb->l4hdroff, skb->priority, skb->qmap); 292 db_printf("\tpkt_type %d dev %p sk %p\n", 293 skb->pkt_type, skb->dev, skb->sk); 294 db_printf("\tcsum_offset %d csum_start %d ip_summed %d protocol %d\n", 295 skb->csum_offset, skb->csum_start, skb->ip_summed, skb->protocol); 296 db_printf("\t_flags %#06x\n", skb->_flags); /* XXX-BZ print names? */ 297 db_printf("\thead %p data %p tail %p end %p\n", 298 skb->head, skb->data, skb->tail, skb->end); 299 db_printf("\tshinfo %p m %p m_free_func %p\n", 300 skb->shinfo, skb->m, skb->m_free_func); 301 302 if (skb->shinfo != NULL) { 303 struct skb_shared_info *shinfo; 304 305 shinfo = skb->shinfo; 306 db_printf("\t\tgso_type %d gso_size %u nr_frags %u\n", 307 shinfo->gso_type, shinfo->gso_size, shinfo->nr_frags); 308 for (i = 0; i < nitems(shinfo->frags); i++) { 309 struct skb_frag *frag; 310 311 frag = &shinfo->frags[i]; 312 if (frag == NULL || frag->page == NULL) 313 continue; 314 db_printf("\t\t\tfrag %p fragno %d page %p %p " 315 "offset %ju size %zu\n", 316 frag, i, frag->page, linux_page_address(frag->page), 317 (uintmax_t)frag->offset, frag->size); 318 } 319 } 320 db_printf("\tcb[] %p {", skb->cb); 321 for (i = 0; i < nitems(skb->cb); i++) { 322 db_printf("%#04x%s", 323 skb->cb[i], (i < (nitems(skb->cb)-1)) ? ", " : ""); 324 } 325 db_printf("}\n"); 326 327 db_printf("\t__scratch[0] %p\n", skb->__scratch); 328 }; 329 #endif 330