Mention updated config files.
[rsync.git] / checksum.c
index 0ce7259dbf32d56fa4c6b76efb2f3d14555cd191..cb21882c5695dff6c3447e1e6da89c4840722162 100644 (file)
-/* 
-   Copyright (C) Andrew Tridgell 1996
-   Copyright (C) Paul Mackerras 1996
-   
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 2 of the License, or
-   (at your option) any later version.
-   
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-   
-   You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
-*/
+/*
+ * Routines to support checksumming of bytes.
+ *
+ * Copyright (C) 1996 Andrew Tridgell
+ * Copyright (C) 1996 Paul Mackerras
+ * Copyright (C) 2004-2023 Wayne Davison
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * In addition, as a special exception, the copyright holders give
+ * permission to dynamically link rsync with the OpenSSL and xxhash
+ * libraries when those libraries are being distributed in compliance
+ * with their license terms, and to distribute a dynamically linked
+ * combination of rsync and these libraries.  This is also considered
+ * to be covered under the GPL's System Libraries exception.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, visit the http://fsf.org website.
+ */
 
 #include "rsync.h"
 
-int csum_length=2; /* initial value */
+#ifdef SUPPORT_XXHASH
+#include <xxhash.h>
+# if XXH_VERSION_NUMBER >= 800
+#  define SUPPORT_XXH3 1
+# endif
+#endif
+
+extern int am_server;
+extern int whole_file;
+extern int checksum_seed;
+extern int protocol_version;
+extern int proper_seed_order;
+extern const char *checksum_choice;
+
+#define NNI_BUILTIN (1<<0)
+#define NNI_EVP (1<<1)
+#define NNI_EVP_OK (1<<2)
+
+struct name_num_item valid_checksums_items[] = {
+#ifdef SUPPORT_XXH3
+       { CSUM_XXH3_128, 0, "xxh128", NULL },
+       { CSUM_XXH3_64, 0, "xxh3", NULL },
+#endif
+#ifdef SUPPORT_XXHASH
+       { CSUM_XXH64, 0, "xxh64", NULL },
+       { CSUM_XXH64, 0, "xxhash", NULL },
+#endif
+       { CSUM_MD5, NNI_BUILTIN|NNI_EVP, "md5", NULL },
+       { CSUM_MD4, NNI_BUILTIN|NNI_EVP, "md4", NULL },
+#ifdef SHA_DIGEST_LENGTH
+       { CSUM_SHA1, NNI_EVP, "sha1", NULL },
+#endif
+       { CSUM_NONE, 0, "none", NULL },
+       { 0, 0, NULL, NULL }
+};
+
+struct name_num_obj valid_checksums = {
+       "checksum", NULL, 0, 0, valid_checksums_items
+};
+
+struct name_num_item valid_auth_checksums_items[] = {
+#ifdef SHA512_DIGEST_LENGTH
+       { CSUM_SHA512, NNI_EVP, "sha512", NULL },
+#endif
+#ifdef SHA256_DIGEST_LENGTH
+       { CSUM_SHA256, NNI_EVP, "sha256", NULL },
+#endif
+#ifdef SHA_DIGEST_LENGTH
+       { CSUM_SHA1, NNI_EVP, "sha1", NULL },
+#endif
+       { CSUM_MD5, NNI_BUILTIN|NNI_EVP, "md5", NULL },
+       { CSUM_MD4, NNI_BUILTIN|NNI_EVP, "md4", NULL },
+       { 0, 0, NULL, NULL }
+};
+
+struct name_num_obj valid_auth_checksums = {
+       "daemon auth checksum", NULL, 0, 0, valid_auth_checksums_items
+};
 
-#define CSUM_CHUNK 64
+/* These cannot make use of openssl, so they're marked just as built-in */
+struct name_num_item implied_checksum_md4 =
+    { CSUM_MD4, NNI_BUILTIN, "md4", NULL };
+struct name_num_item implied_checksum_md5 =
+    { CSUM_MD5, NNI_BUILTIN, "md5", NULL };
 
-int checksum_seed = 0;
-extern int remote_version;
+struct name_num_item *xfer_sum_nni; /* used for the transfer checksum2 computations */
+int xfer_sum_len;
+struct name_num_item *file_sum_nni; /* used for the pre-transfer --checksum computations */
+int file_sum_len, file_sum_extra_cnt;
 
+#ifdef USE_OPENSSL
+const EVP_MD *xfer_sum_evp_md;
+const EVP_MD *file_sum_evp_md;
+EVP_MD_CTX *ctx_evp = NULL;
+#endif
+
+static int initialized_choices = 0;
+
+struct name_num_item *parse_csum_name(const char *name, int len)
+{
+       struct name_num_item *nni;
+
+       if (len < 0 && name)
+               len = strlen(name);
+
+       init_checksum_choices();
+
+       if (!name || (len == 4 && strncasecmp(name, "auto", 4) == 0)) {
+               if (protocol_version >= 30) {
+                       if (!proper_seed_order)
+                               return &implied_checksum_md5;
+                       name = "md5";
+                       len = 3;
+               } else {
+                       if (protocol_version >= 27)
+                               implied_checksum_md4.num = CSUM_MD4_OLD;
+                       else if (protocol_version >= 21)
+                               implied_checksum_md4.num = CSUM_MD4_BUSTED;
+                       else
+                               implied_checksum_md4.num = CSUM_MD4_ARCHAIC;
+                       return &implied_checksum_md4;
+               }
+       }
+
+       nni = get_nni_by_name(&valid_checksums, name, len);
+
+       if (!nni) {
+               rprintf(FERROR, "unknown checksum name: %s\n", name);
+               exit_cleanup(RERR_UNSUPPORTED);
+       }
+
+       return nni;
+}
+
+#ifdef USE_OPENSSL
+static const EVP_MD *csum_evp_md(struct name_num_item *nni)
+{
+       const EVP_MD *emd;
+       if (!(nni->flags & NNI_EVP))
+               return NULL;
+
+#ifdef USE_MD5_ASM
+       if (nni->num == CSUM_MD5)
+               emd = NULL;
+       else
+#endif
+               emd = EVP_get_digestbyname(nni->name);
+       if (emd && !(nni->flags & NNI_EVP_OK)) { /* Make sure it works before we advertise it */
+               if (!ctx_evp && !(ctx_evp = EVP_MD_CTX_create()))
+                       out_of_memory("csum_evp_md");
+               /* Some routines are marked as legacy and are not enabled in the openssl.cnf file.
+                * If we can't init the emd, we'll fall back to our built-in code. */
+               if (EVP_DigestInit_ex(ctx_evp, emd, NULL) == 0)
+                       emd = NULL;
+               else
+                       nni->flags = (nni->flags & ~NNI_BUILTIN) | NNI_EVP_OK;
+       }
+       if (!emd)
+               nni->flags &= ~NNI_EVP;
+       return emd;
+}
+#endif
+
+void parse_checksum_choice(int final_call)
+{
+       if (valid_checksums.negotiated_nni)
+               xfer_sum_nni = file_sum_nni = valid_checksums.negotiated_nni;
+       else {
+               char *cp = checksum_choice ? strchr(checksum_choice, ',') : NULL;
+               if (cp) {
+                       xfer_sum_nni = parse_csum_name(checksum_choice, cp - checksum_choice);
+                       file_sum_nni = parse_csum_name(cp+1, -1);
+               } else
+                       xfer_sum_nni = file_sum_nni = parse_csum_name(checksum_choice, -1);
+               if (am_server && checksum_choice)
+                       validate_choice_vs_env(NSTR_CHECKSUM, xfer_sum_nni->num, file_sum_nni->num);
+       }
+       xfer_sum_len = csum_len_for_type(xfer_sum_nni->num, 0);
+       file_sum_len = csum_len_for_type(file_sum_nni->num, 0);
+#ifdef USE_OPENSSL
+       xfer_sum_evp_md = csum_evp_md(xfer_sum_nni);
+       file_sum_evp_md = csum_evp_md(file_sum_nni);
+#endif
+
+       file_sum_extra_cnt = (file_sum_len + EXTRA_LEN - 1) / EXTRA_LEN;
+
+       if (xfer_sum_nni->num == CSUM_NONE)
+               whole_file = 1;
+
+       /* Snag the checksum name for both write_batch's option output & the following debug output. */
+       if (valid_checksums.negotiated_nni)
+               checksum_choice = valid_checksums.negotiated_nni->name;
+       else if (checksum_choice == NULL)
+               checksum_choice = xfer_sum_nni->name;
+
+       if (final_call && DEBUG_GTE(NSTR, am_server ? 3 : 1)) {
+               rprintf(FINFO, "%s%s checksum: %s\n",
+                       am_server ? "Server" : "Client",
+                       valid_checksums.negotiated_nni ? " negotiated" : "",
+                       checksum_choice);
+       }
+}
+
+int csum_len_for_type(int cst, BOOL flist_csum)
+{
+       switch (cst) {
+         case CSUM_NONE:
+               return 1;
+         case CSUM_MD4_ARCHAIC:
+               /* The oldest checksum code is rather weird: the file-list code only sent
+                * 2-byte checksums, but all other checksums were full MD4 length. */
+               return flist_csum ? 2 : MD4_DIGEST_LEN;
+         case CSUM_MD4:
+         case CSUM_MD4_OLD:
+         case CSUM_MD4_BUSTED:
+               return MD4_DIGEST_LEN;
+         case CSUM_MD5:
+               return MD5_DIGEST_LEN;
+#ifdef SHA_DIGEST_LENGTH
+         case CSUM_SHA1:
+               return SHA_DIGEST_LENGTH;
+#endif
+#ifdef SHA256_DIGEST_LENGTH
+         case CSUM_SHA256:
+               return SHA256_DIGEST_LENGTH;
+#endif
+#ifdef SHA512_DIGEST_LENGTH
+         case CSUM_SHA512:
+               return SHA512_DIGEST_LENGTH;
+#endif
+         case CSUM_XXH64:
+         case CSUM_XXH3_64:
+               return 64/8;
+         case CSUM_XXH3_128:
+               return 128/8;
+         default: /* paranoia to prevent missing case values */
+               exit_cleanup(RERR_UNSUPPORTED);
+       }
+       return 0;
+}
+
+/* Returns 0 if the checksum is not canonical (i.e. it includes a seed value).
+ * Returns 1 if the public sum order matches our internal sum order.
+ * Returns -1 if the public sum order is the reverse of our internal sum order.
+ */
+int canonical_checksum(int csum_type)
+{
+       switch (csum_type) {
+         case CSUM_NONE:
+         case CSUM_MD4_ARCHAIC:
+         case CSUM_MD4_OLD:
+         case CSUM_MD4_BUSTED:
+               break;
+         case CSUM_MD4:
+         case CSUM_MD5:
+         case CSUM_SHA1:
+         case CSUM_SHA256:
+         case CSUM_SHA512:
+               return -1;
+         case CSUM_XXH64:
+         case CSUM_XXH3_64:
+         case CSUM_XXH3_128:
+               return 1;
+         default: /* paranoia to prevent missing case values */
+               exit_cleanup(RERR_UNSUPPORTED);
+       }
+       return 0;
+}
+
+#ifndef USE_ROLL_SIMD /* See simd-checksum-*.cpp. */
 /*
-  a simple 32 bit checksum that can be upadted from either end
+  a simple 32 bit checksum that can be updated from either end
   (inspired by Mark Adler's Adler-32 checksum)
   */
-uint32 get_checksum1(char *buf1,int len)
+uint32 get_checksum1(char *buf1, int32 len)
 {
-    int i;
-    uint32 s1, s2;
-    schar *buf = (schar *)buf1;
-
-    s1 = s2 = 0;
-    for (i = 0; i < (len-4); i+=4) {
-       s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] + 
-         10*CHAR_OFFSET;
-       s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET); 
-    }
-    for (; i < len; i++) {
-       s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
-    }
-    return (s1 & 0xffff) + (s2 << 16);
-}
+       int32 i;
+       uint32 s1, s2;
+       schar *buf = (schar *)buf1;
 
+       s1 = s2 = 0;
+       for (i = 0; i < (len-4); i+=4) {
+               s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] + 10*CHAR_OFFSET;
+               s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
+       }
+       for (; i < len; i++) {
+               s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
+       }
+       return (s1 & 0xffff) + (s2 << 16);
+}
+#endif
 
-void get_checksum2(char *buf,int len,char *sum)
+/* The "sum" buffer must be at least MAX_DIGEST_LEN bytes! */
+void get_checksum2(char *buf, int32 len, char *sum)
 {
-       int i;
-       static char *buf1;
-       static int len1;
-       struct mdfour m;
-
-       if (len > len1) {
-               if (buf1) free(buf1);
-               buf1 = (char *)malloc(len+4);
-               len1 = len;
-               if (!buf1) out_of_memory("get_checksum2");
-       }
-       
-       mdfour_begin(&m);
-       
-       memcpy(buf1,buf,len);
-       if (checksum_seed) {
-               SIVAL(buf1,len,checksum_seed);
-               len += 4;
-       }
-       
-       for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
-               mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
-       }
-       if (len - i > 0) {
-               mdfour_update(&m, (uchar *)(buf1+i), (len-i));
-       }
-       
-       mdfour_result(&m, (uchar *)sum);
-}
+#ifdef USE_OPENSSL
+       if (xfer_sum_evp_md) {
+               static EVP_MD_CTX *evp = NULL;
+               uchar seedbuf[4];
+               if (!evp && !(evp = EVP_MD_CTX_create()))
+                       out_of_memory("get_checksum2");
+               EVP_DigestInit_ex(evp, xfer_sum_evp_md, NULL);
+               if (checksum_seed) {
+                       SIVALu(seedbuf, 0, checksum_seed);
+                       EVP_DigestUpdate(evp, seedbuf, 4);
+               }
+               EVP_DigestUpdate(evp, (uchar *)buf, len);
+               EVP_DigestFinal_ex(evp, (uchar *)sum, NULL);
+       } else
+#endif
+       switch (xfer_sum_nni->num) {
+#ifdef SUPPORT_XXHASH
+         case CSUM_XXH64:
+               SIVAL64(sum, 0, XXH64(buf, len, checksum_seed));
+               break;
+#endif
+#ifdef SUPPORT_XXH3
+         case CSUM_XXH3_64:
+               SIVAL64(sum, 0, XXH3_64bits_withSeed(buf, len, checksum_seed));
+               break;
+         case CSUM_XXH3_128: {
+               XXH128_hash_t digest = XXH3_128bits_withSeed(buf, len, checksum_seed);
+               SIVAL64(sum, 0, digest.low64);
+               SIVAL64(sum, 8, digest.high64);
+               break;
+         }
+#endif
+         case CSUM_MD5: {
+               md_context m5;
+               uchar seedbuf[4];
+               md5_begin(&m5);
+               if (proper_seed_order) {
+                       if (checksum_seed) {
+                               SIVALu(seedbuf, 0, checksum_seed);
+                               md5_update(&m5, seedbuf, 4);
+                       }
+                       md5_update(&m5, (uchar *)buf, len);
+               } else {
+                       md5_update(&m5, (uchar *)buf, len);
+                       if (checksum_seed) {
+                               SIVALu(seedbuf, 0, checksum_seed);
+                               md5_update(&m5, seedbuf, 4);
+                       }
+               }
+               md5_result(&m5, (uchar *)sum);
+               break;
+         }
+         case CSUM_MD4:
+         case CSUM_MD4_OLD:
+         case CSUM_MD4_BUSTED:
+         case CSUM_MD4_ARCHAIC: {
+               md_context m;
+               int32 i;
+               static char *buf1;
+               static int32 len1;
 
+               mdfour_begin(&m);
+
+               if (len > len1) {
+                       if (buf1)
+                               free(buf1);
+                       buf1 = new_array(char, len+4);
+                       len1 = len;
+               }
+
+               memcpy(buf1, buf, len);
+               if (checksum_seed) {
+                       SIVAL(buf1,len,checksum_seed);
+                       len += 4;
+               }
+
+               for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
+                       mdfour_update(&m, (uchar *)(buf1+i), CSUM_CHUNK);
+
+               /*
+                * Prior to version 27 an incorrect MD4 checksum was computed
+                * by failing to call mdfour_tail() for block sizes that
+                * are multiples of 64.  This is fixed by calling mdfour_update()
+                * even when there are no more bytes.
+                */
+               if (len - i > 0 || xfer_sum_nni->num > CSUM_MD4_BUSTED)
+                       mdfour_update(&m, (uchar *)(buf1+i), len-i);
+
+               mdfour_result(&m, (uchar *)sum);
+               break;
+         }
+         default: /* paranoia to prevent missing case values */
+               exit_cleanup(RERR_UNSUPPORTED);
+       }
+}
 
-void file_checksum(char *fname,char *sum,OFF_T size)
+void file_checksum(const char *fname, const STRUCT_STAT *st_p, char *sum)
 {
-       OFF_T i;
        struct map_struct *buf;
+       OFF_T i, len = st_p->st_size;
+       int32 remainder;
        int fd;
-       OFF_T len = size;
-       char tmpchunk[CSUM_CHUNK];
-       struct mdfour m;
-       
-       memset(sum,0,MD4_SUM_LENGTH);
-       
-       fd = do_open(fname, O_RDONLY, 0);
-       if (fd == -1) return;
-       
-       buf = map_file(fd,size);
-       
-       mdfour_begin(&m);
 
-       for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
-               memcpy(tmpchunk, map_ptr(buf,i,CSUM_CHUNK), CSUM_CHUNK);
-               mdfour_update(&m, (uchar *)tmpchunk, CSUM_CHUNK);
+       fd = do_open(fname, O_RDONLY, 0);
+       if (fd == -1) {
+               memset(sum, 0, file_sum_len);
+               return;
        }
 
-       if (len - i > 0) {
-               memcpy(tmpchunk, map_ptr(buf,i,len-i), len-i);
-               mdfour_update(&m, (uchar *)tmpchunk, (len-i));
-       }
+       buf = map_file(fd, len, MAX_MAP_SIZE, CHUNK_SIZE);
+
+#ifdef USE_OPENSSL
+       if (file_sum_evp_md) {
+               static EVP_MD_CTX *evp = NULL;
+               if (!evp && !(evp = EVP_MD_CTX_create()))
+                       out_of_memory("file_checksum");
+
+               EVP_DigestInit_ex(evp, file_sum_evp_md, NULL);
+
+               for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+                       EVP_DigestUpdate(evp, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+
+               remainder = (int32)(len - i);
+               if (remainder > 0)
+                       EVP_DigestUpdate(evp, (uchar *)map_ptr(buf, i, remainder), remainder);
+
+               EVP_DigestFinal_ex(evp, (uchar *)sum, NULL);
+       } else
+#endif
+       switch (file_sum_nni->num) {
+#ifdef SUPPORT_XXHASH
+         case CSUM_XXH64: {
+               static XXH64_state_t* state = NULL;
+               if (!state && !(state = XXH64_createState()))
+                       out_of_memory("file_checksum");
+
+               XXH64_reset(state, 0);
+
+               for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+                       XXH64_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+
+               remainder = (int32)(len - i);
+               if (remainder > 0)
+                       XXH64_update(state, (uchar *)map_ptr(buf, i, remainder), remainder);
+
+               SIVAL64(sum, 0, XXH64_digest(state));
+               break;
+         }
+#endif
+#ifdef SUPPORT_XXH3
+         case CSUM_XXH3_64: {
+               static XXH3_state_t* state = NULL;
+               if (!state && !(state = XXH3_createState()))
+                       out_of_memory("file_checksum");
+
+               XXH3_64bits_reset(state);
+
+               for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+                       XXH3_64bits_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+
+               remainder = (int32)(len - i);
+               if (remainder > 0)
+                       XXH3_64bits_update(state, (uchar *)map_ptr(buf, i, remainder), remainder);
+
+               SIVAL64(sum, 0, XXH3_64bits_digest(state));
+               break;
+         }
+         case CSUM_XXH3_128: {
+               XXH128_hash_t digest;
+               static XXH3_state_t* state = NULL;
+               if (!state && !(state = XXH3_createState()))
+                       out_of_memory("file_checksum");
+
+               XXH3_128bits_reset(state);
+
+               for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+                       XXH3_128bits_update(state, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+
+               remainder = (int32)(len - i);
+               if (remainder > 0)
+                       XXH3_128bits_update(state, (uchar *)map_ptr(buf, i, remainder), remainder);
+
+               digest = XXH3_128bits_digest(state);
+               SIVAL64(sum, 0, digest.low64);
+               SIVAL64(sum, 8, digest.high64);
+               break;
+         }
+#endif
+         case CSUM_MD5: {
+               md_context m5;
+
+               md5_begin(&m5);
+
+               for (i = 0; i + CHUNK_SIZE <= len; i += CHUNK_SIZE)
+                       md5_update(&m5, (uchar *)map_ptr(buf, i, CHUNK_SIZE), CHUNK_SIZE);
+
+               remainder = (int32)(len - i);
+               if (remainder > 0)
+                       md5_update(&m5, (uchar *)map_ptr(buf, i, remainder), remainder);
+
+               md5_result(&m5, (uchar *)sum);
+               break;
+         }
+         case CSUM_MD4:
+         case CSUM_MD4_OLD:
+         case CSUM_MD4_BUSTED:
+         case CSUM_MD4_ARCHAIC: {
+               md_context m;
+
+               mdfour_begin(&m);
 
-       mdfour_result(&m, (uchar *)sum);
+               for (i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK)
+                       mdfour_update(&m, (uchar *)map_ptr(buf, i, CSUM_CHUNK), CSUM_CHUNK);
+
+               /* Prior to version 27 an incorrect MD4 checksum was computed
+                * by failing to call mdfour_tail() for block sizes that
+                * are multiples of 64.  This is fixed by calling mdfour_update()
+                * even when there are no more bytes. */
+               remainder = (int32)(len - i);
+               if (remainder > 0 || file_sum_nni->num > CSUM_MD4_BUSTED)
+                       mdfour_update(&m, (uchar *)map_ptr(buf, i, remainder), remainder);
+
+               mdfour_result(&m, (uchar *)sum);
+               break;
+         }
+         default:
+               rprintf(FERROR, "Invalid checksum-choice for --checksum: %s (%d)\n",
+                       file_sum_nni->name, file_sum_nni->num);
+               exit_cleanup(RERR_UNSUPPORTED);
+       }
 
        close(fd);
        unmap_file(buf);
 }
 
+static int32 sumresidue;
+static md_context ctx_md;
+#ifdef SUPPORT_XXHASH
+static XXH64_state_t* xxh64_state;
+#endif
+#ifdef SUPPORT_XXH3
+static XXH3_state_t* xxh3_state;
+#endif
+static struct name_num_item *cur_sum_nni;
+int cur_sum_len;
+
+#ifdef USE_OPENSSL
+static const EVP_MD *cur_sum_evp_md;
+#endif
 
-void checksum_init(void)
+/* Initialize a hash digest accumulator.  Data is supplied via
+ * sum_update() and the resulting binary digest is retrieved via
+ * sum_end().  This only supports one active sum at a time. */
+int sum_init(struct name_num_item *nni, int seed)
 {
-  if (remote_version >= 14)
-    csum_length = 2; /* adaptive */
-  else
-    csum_length = SUM_LENGTH;
-}
+       char s[4];
 
+       if (!nni)
+               nni = parse_csum_name(NULL, 0);
+       cur_sum_nni = nni;
+       cur_sum_len = csum_len_for_type(nni->num, 0);
+#ifdef USE_OPENSSL
+       cur_sum_evp_md = csum_evp_md(nni);
+#endif
 
+#ifdef USE_OPENSSL
+       if (cur_sum_evp_md) {
+               if (!ctx_evp && !(ctx_evp = EVP_MD_CTX_create()))
+                       out_of_memory("file_checksum");
+               EVP_DigestInit_ex(ctx_evp, cur_sum_evp_md, NULL);
+       } else
+#endif
+       switch (cur_sum_nni->num) {
+#ifdef SUPPORT_XXHASH
+         case CSUM_XXH64:
+               if (!xxh64_state && !(xxh64_state = XXH64_createState()))
+                       out_of_memory("sum_init");
+               XXH64_reset(xxh64_state, 0);
+               break;
+#endif
+#ifdef SUPPORT_XXH3
+         case CSUM_XXH3_64:
+               if (!xxh3_state && !(xxh3_state = XXH3_createState()))
+                       out_of_memory("sum_init");
+               XXH3_64bits_reset(xxh3_state);
+               break;
+         case CSUM_XXH3_128:
+               if (!xxh3_state && !(xxh3_state = XXH3_createState()))
+                       out_of_memory("sum_init");
+               XXH3_128bits_reset(xxh3_state);
+               break;
+#endif
+         case CSUM_MD5:
+               md5_begin(&ctx_md);
+               break;
+         case CSUM_MD4:
+               mdfour_begin(&ctx_md);
+               sumresidue = 0;
+               break;
+         case CSUM_MD4_OLD:
+         case CSUM_MD4_BUSTED:
+         case CSUM_MD4_ARCHAIC:
+               mdfour_begin(&ctx_md);
+               sumresidue = 0;
+               SIVAL(s, 0, seed);
+               sum_update(s, 4);
+               break;
+         case CSUM_NONE:
+               break;
+         default: /* paranoia to prevent missing case values */
+               exit_cleanup(RERR_UNSUPPORTED);
+       }
 
-static int sumresidue;
-static char sumrbuf[CSUM_CHUNK];
-static struct mdfour md;
+       return cur_sum_len;
+}
 
-void sum_init(void)
+/* Feed data into a hash digest accumulator. */
+void sum_update(const char *p, int32 len)
 {
-       char s[4];
-       mdfour_begin(&md);
-       sumresidue=0;
-       SIVAL(s,0,checksum_seed);
-       sum_update(s,4);
+#ifdef USE_OPENSSL
+       if (cur_sum_evp_md) {
+               EVP_DigestUpdate(ctx_evp, (uchar *)p, len);
+       } else
+#endif
+       switch (cur_sum_nni->num) {
+#ifdef SUPPORT_XXHASH
+         case CSUM_XXH64:
+               XXH64_update(xxh64_state, p, len);
+               break;
+#endif
+#ifdef SUPPORT_XXH3
+         case CSUM_XXH3_64:
+               XXH3_64bits_update(xxh3_state, p, len);
+               break;
+         case CSUM_XXH3_128:
+               XXH3_128bits_update(xxh3_state, p, len);
+               break;
+#endif
+         case CSUM_MD5:
+               md5_update(&ctx_md, (uchar *)p, len);
+               break;
+         case CSUM_MD4:
+         case CSUM_MD4_OLD:
+         case CSUM_MD4_BUSTED:
+         case CSUM_MD4_ARCHAIC:
+               if (len + sumresidue < CSUM_CHUNK) {
+                       memcpy(ctx_md.buffer + sumresidue, p, len);
+                       sumresidue += len;
+                       break;
+               }
+
+               if (sumresidue) {
+                       int32 i = CSUM_CHUNK - sumresidue;
+                       memcpy(ctx_md.buffer + sumresidue, p, i);
+                       mdfour_update(&ctx_md, (uchar *)ctx_md.buffer, CSUM_CHUNK);
+                       len -= i;
+                       p += i;
+               }
+
+               while (len >= CSUM_CHUNK) {
+                       mdfour_update(&ctx_md, (uchar *)p, CSUM_CHUNK);
+                       len -= CSUM_CHUNK;
+                       p += CSUM_CHUNK;
+               }
+
+               sumresidue = len;
+               if (sumresidue)
+                       memcpy(ctx_md.buffer, p, sumresidue);
+               break;
+         case CSUM_NONE:
+               break;
+         default: /* paranoia to prevent missing case values */
+               exit_cleanup(RERR_UNSUPPORTED);
+       }
 }
 
-void sum_update(char *p,int len)
+/* The sum buffer only needs to be as long as the current checksum's digest
+ * len, not MAX_DIGEST_LEN. Note that for CSUM_MD4_ARCHAIC that is the full
+ * MD4_DIGEST_LEN even if the file-list code is going to ignore all but the
+ * first 2 bytes of it. */
+void sum_end(char *sum)
 {
-       int i;
-       if (len + sumresidue < CSUM_CHUNK) {
-               memcpy(sumrbuf+sumresidue, p, len);
-               sumresidue += len;
-               return;
+#ifdef USE_OPENSSL
+       if (cur_sum_evp_md) {
+               EVP_DigestFinal_ex(ctx_evp, (uchar *)sum, NULL);
+       } else
+#endif
+       switch (cur_sum_nni->num) {
+#ifdef SUPPORT_XXHASH
+         case CSUM_XXH64:
+               SIVAL64(sum, 0, XXH64_digest(xxh64_state));
+               break;
+#endif
+#ifdef SUPPORT_XXH3
+         case CSUM_XXH3_64:
+               SIVAL64(sum, 0, XXH3_64bits_digest(xxh3_state));
+               break;
+         case CSUM_XXH3_128: {
+               XXH128_hash_t digest = XXH3_128bits_digest(xxh3_state);
+               SIVAL64(sum, 0, digest.low64);
+               SIVAL64(sum, 8, digest.high64);
+               break;
+         }
+#endif
+         case CSUM_MD5:
+               md5_result(&ctx_md, (uchar *)sum);
+               break;
+         case CSUM_MD4:
+         case CSUM_MD4_OLD:
+               mdfour_update(&ctx_md, (uchar *)ctx_md.buffer, sumresidue);
+               mdfour_result(&ctx_md, (uchar *)sum);
+               break;
+         case CSUM_MD4_BUSTED:
+         case CSUM_MD4_ARCHAIC:
+               if (sumresidue)
+                       mdfour_update(&ctx_md, (uchar *)ctx_md.buffer, sumresidue);
+               mdfour_result(&ctx_md, (uchar *)sum);
+               break;
+         case CSUM_NONE:
+               *sum = '\0';
+               break;
+         default: /* paranoia to prevent missing case values */
+               exit_cleanup(RERR_UNSUPPORTED);
        }
+}
 
-       if (sumresidue) {
-               i = MIN(CSUM_CHUNK-sumresidue,len);
-               memcpy(sumrbuf+sumresidue,p,i);
-               mdfour_update(&md, (uchar *)sumrbuf, (i+sumresidue));
-               len -= i;
-               p += i;
-       }
+#if defined SUPPORT_XXH3 || defined USE_OPENSSL
+static void verify_digest(struct name_num_item *nni, BOOL check_auth_list)
+{
+#ifdef SUPPORT_XXH3
+       static int xxh3_result = 0;
+#endif
+#ifdef USE_OPENSSL
+       static int prior_num = 0, prior_flags = 0, prior_result = 0;
+#endif
 
-       for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
-               memcpy(sumrbuf,p+i,CSUM_CHUNK);
-               mdfour_update(&md, (uchar *)sumrbuf, CSUM_CHUNK);
+#ifdef SUPPORT_XXH3
+       if (nni->num == CSUM_XXH3_64 || nni->num == CSUM_XXH3_128) {
+               if (!xxh3_result) {
+                       char buf[32816];
+                       int j;
+                       for (j = 0; j < (int)sizeof buf; j++)
+                               buf[j] = ' ' + (j % 96);
+                       sum_init(nni, 0);
+                       sum_update(buf, 32816);
+                       sum_update(buf, 31152);
+                       sum_update(buf, 32474);
+                       sum_update(buf, 9322);
+                       xxh3_result = XXH3_64bits_digest(xxh3_state) != 0xadbcf16d4678d1de ? -1 : 1;
+               }
+               if (xxh3_result < 0)
+                       nni->num = CSUM_gone;
+               return;
        }
+#endif
 
-       if (len - i > 0) {
-               sumresidue = len-i;
-               memcpy(sumrbuf,p+i,sumresidue);
-       } else {
-               sumresidue = 0;    
+#ifdef USE_OPENSSL
+       if (BITS_SETnUNSET(nni->flags, NNI_EVP, NNI_BUILTIN|NNI_EVP_OK)) {
+               if (nni->num == prior_num && nni->flags == prior_flags) {
+                       nni->flags = prior_result;
+                       if (!(nni->flags & NNI_EVP))
+                               nni->num = CSUM_gone;
+               } else {
+                       prior_num = nni->num;
+                       prior_flags = nni->flags;
+                       if (!csum_evp_md(nni))
+                               nni->num = CSUM_gone;
+                       prior_result = nni->flags;
+                       if (check_auth_list && (nni = get_nni_by_num(&valid_auth_checksums, prior_num)) != NULL)
+                               verify_digest(nni, False);
+               }
        }
+#endif
 }
+#endif
 
-void sum_end(char *sum)
+void init_checksum_choices()
 {
-       if (sumresidue) {
-               mdfour_update(&md, (uchar *)sumrbuf, sumresidue);
-       }
+#if defined SUPPORT_XXH3 || defined USE_OPENSSL
+       struct name_num_item *nni;
+#endif
+
+       if (initialized_choices)
+               return;
+
+#if defined USE_OPENSSL && OPENSSL_VERSION_NUMBER < 0x10100000L
+       OpenSSL_add_all_algorithms();
+#endif
+
+#if defined SUPPORT_XXH3 || defined USE_OPENSSL
+       for (nni = valid_checksums.list; nni->name; nni++)
+               verify_digest(nni, True);
+
+       for (nni = valid_auth_checksums.list; nni->name; nni++)
+               verify_digest(nni, False);
+#endif
 
-       mdfour_result(&md, (uchar *)sum);
+       initialized_choices = 1;
 }