first partial draft of featureEmail, not finished

Builds/CMake/RippledCore.cmake

@@ -542,7 +542,6 @@ target_sources (rippled PRIVATE
   src/ripple/nodestore/backend/NuDBFactory.cpp
   src/ripple/nodestore/backend/NullFactory.cpp
   src/ripple/nodestore/backend/RocksDBFactory.cpp
-  src/ripple/nodestore/backend/SnugDBFactory.cpp
   src/ripple/nodestore/impl/BatchWriter.cpp
   src/ripple/nodestore/impl/Database.cpp
   src/ripple/nodestore/impl/DatabaseNodeImp.cpp

build-full.sh

@@ -9,15 +9,6 @@ echo "-- GITHUB_RUN_NUMBER: $4"
 
 umask 0000;
 
-echo "Fixing CentOS 7 EOL"
-
-sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*
-sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*
-yum clean all
-yum-config-manager --disable centos-sclo-sclo
-
-####
-
 cd /io;
 mkdir src/certs;
 curl --silent -k https://raw.githubusercontent.com/RichardAH/rippled-release-builder/main/ca-bundle/certbundle.h -o src/certs/certbundle.h;

src/ripple/core/impl/Config.cpp

@@ -127,7 +127,7 @@ sizedItems
     {SizedItem::txnDBCache,         {{      4,      12,      24,      64,     128 }}},
     {SizedItem::lgrDBCache,         {{      4,       8,      16,      32,     128 }}},
     {SizedItem::openFinalLimit,     {{      8,      16,      32,      64,     128 }}},
-    {SizedItem::burstSize,          {{      4,       8,      16,      32,      64*1024*1024 }}},
+    {SizedItem::burstSize,          {{      4,       8,      16,      32,      48 }}},
     {SizedItem::ramSizeGB,          {{      8,      12,      16,      24,      32 }}},
     {SizedItem::accountIdCacheSize, {{  20047,   50053,   77081,  150061,  300007 }}}
 }};

src/ripple/nodestore/backend/SnugDBFactory.cpp

@@ -1,336 +0,0 @@
-//------------------------------------------------------------------------------
-/*
-    This file is part of rippled: https://github.com/ripple/rippled
-    Copyright (c) 2012, 2013 Ripple Labs Inc.
-
-    Permission to use, copy, modify, and/or distribute this software for any
-    purpose  with  or without fee is hereby granted, provided that the above
-    copyright notice and this permission notice appear in all copies.
-
-    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
-    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
-    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
-    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
-    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
-    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
-    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
-*/
-//==============================================================================
-
-#include <ripple/basics/contract.h>
-#include <ripple/nodestore/Factory.h>
-#include <ripple/nodestore/Manager.h>
-#include <ripple/nodestore/impl/DecodedBlob.h>
-#include <ripple/nodestore/impl/EncodedBlob.h>
-#include <ripple/nodestore/impl/codec.h>
-#include <boost/filesystem.hpp>
-#include "snug.hpp"
-#include <cassert>
-#include <chrono>
-#include <cstdint>
-#include <cstdio>
-#include <exception>
-#include <memory>
-
-namespace ripple {
-namespace NodeStore {
-
-class SnugDBBackend : public Backend
-{
-private:
-    static constexpr uint64_t BUFFER_SIZE =
-        256ULL * 1024ULL * 1024ULL;  // 256 Mib read buffer per thread
-public:
-    beast::Journal const j_;
-    std::string const name_;
-    std::unique_ptr<snug::SnugDB> db_;
-    Scheduler& scheduler_;
-
-    SnugDBBackend(
-        Section const& keyValues,
-        Scheduler& scheduler,
-        beast::Journal journal)
-        : j_(journal), name_(get(keyValues, "path")), scheduler_(scheduler)
-    {
-        if (name_.empty())
-            throw std::runtime_error(
-                "nodestore: Missing path in SnugDB backend");
-    }
-
-    ~SnugDBBackend() override
-    {
-        try
-        {
-            // close can throw and we don't want the destructor to throw.
-            db_ = nullptr;
-        }
-        catch (std::exception const& e)
-        {
-            JLOG(j_.warn()) << "SnugDB threw on destruction: " << e.what();
-            // Don't allow exceptions to propagate out of destructors.
-        }
-    }
-
-    std::string
-    getName() override
-    {
-        return name_;
-    }
-
-    void
-    open(bool createIfMissing, uint64_t appType, uint64_t uid, uint64_t salt)
-        override
-    {
-        if (db_)
-        {
-            assert(false);
-            JLOG(j_.error()) << "database is already open";
-            return;
-        }
-
-        std::string path = name_ + "/" + std::to_string(uid) + "-" +
-            std::to_string(appType) + "-" + std::to_string(salt);
-
-        boost::filesystem::create_directories(path);
-        db_ = std::make_unique<snug::SnugDB>(path);
-    }
-
-    bool
-    isOpen() override
-    {
-        return db_ != nullptr;
-    }
-
-    void
-    open(bool createIfMissing) override
-    {
-        open(createIfMissing, 0, 0, 0);
-    }
-
-    void
-    close() override
-    {
-        db_ = nullptr;
-    }
-
-    Status
-    fetch(void const* key, std::shared_ptr<NodeObject>* pno) override
-    {
-        if (!db_)
-            return backendError;
-
-        pno->reset();
-
-        static thread_local std::unique_ptr<uint8_t[]> thread_buffer =
-            std::make_unique<uint8_t[]>(BUFFER_SIZE);
-
-        uint8_t* ptr = &(thread_buffer[0]);
-
-        uint64_t len = BUFFER_SIZE;
-        int result = db_->read_entry(
-            static_cast<uint8_t*>(const_cast<void*>(key)), ptr, &len);
-
-        if (0)
-        {
-            std::stringstream ss;
-            const unsigned char* bytes = static_cast<const unsigned char*>(key);
-            for (int i = 0; i < 32; ++i)
-            {
-                ss << std::setfill('0') << std::setw(2) << std::hex
-                   << static_cast<int>(bytes[i]);
-            }
-            std::string key_hex = ss.str();
-
-            // Print the result using printf
-            printf(
-                "snug fetch: len=%zu result=%zu key=%s\n",
-                len,
-                result,
-                key_hex.c_str());
-        }
-
-        if (result == 1)
-            return notFound;
-
-        if (result == 0)
-        {
-            DecodedBlob decoded(key, ptr, len);
-            if (!decoded.wasOk())
-                return dataCorrupt;
-
-            *pno = decoded.createObject();
-            return ok;
-        }
-
-        return backendError;
-    }
-
-    std::pair<std::vector<std::shared_ptr<NodeObject>>, Status>
-    fetchBatch(std::vector<uint256 const*> const& hashes) override
-    {
-        std::vector<std::shared_ptr<NodeObject>> results;
-        results.reserve(hashes.size());
-        for (auto const& h : hashes)
-        {
-            std::shared_ptr<NodeObject> nObj;
-            Status status = fetch(h->begin(), &nObj);
-            if (status != ok)
-                results.push_back({});
-            else
-                results.push_back(nObj);
-        }
-
-        return {results, ok};
-    }
-
-    void
-    do_insert(std::shared_ptr<NodeObject> const& no)
-    {
-        EncodedBlob e(no);
-
-        if (0)
-        {
-            std::stringstream ss;
-            const unsigned char* bytes = static_cast<const unsigned char*>(
-                const_cast<void*>(e.getKey()));
-            for (int i = 0; i < 32; ++i)
-                ss << std::setfill('0') << std::setw(2) << std::hex
-                   << static_cast<int>(bytes[i]);
-            std::string key_hex = ss.str();
-
-            std::cout << "snugdb write: len=" << e.getSize()
-                      << ", key=" << key_hex << "\n";
-        }
-        int out = db_->write_entry(
-            static_cast<uint8_t*>(const_cast<void*>(e.getKey())),
-            static_cast<uint8_t*>(const_cast<void*>(e.getData())),
-            e.getSize());
-        if (out != 0)
-            throw std::runtime_error(
-                "SnugDB could not write entry. Disk full? error" +
-                std::to_string(out));
-    }
-
-    void
-    store(std::shared_ptr<NodeObject> const& no) override
-    {
-        BatchWriteReport report;
-        report.writeCount = 1;
-        auto const start = std::chrono::steady_clock::now();
-        do_insert(no);
-        report.elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
-            std::chrono::steady_clock::now() - start);
-        scheduler_.onBatchWrite(report);
-    }
-
-    void
-    storeBatch(Batch const& batch) override
-    {
-        BatchWriteReport report;
-        report.writeCount = batch.size();
-        auto const start = std::chrono::steady_clock::now();
-        for (auto const& e : batch)
-            do_insert(e);
-        report.elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
-            std::chrono::steady_clock::now() - start);
-        scheduler_.onBatchWrite(report);
-    }
-
-    void
-    sync() override
-    {
-    }
-
-    void
-    for_each(std::function<void(std::shared_ptr<NodeObject>)> f) override
-    {
-        db_->visit_all(
-            [](uint8_t* key, uint8_t* data, uint64_t len, void* fp) -> void {
-                DecodedBlob decoded(key, data, len);
-                if (!decoded.wasOk())
-                {
-                    throw std::runtime_error(
-                        "Missing or corrupted data in snugdb");
-                    return;
-                }
-
-                std::function<void(std::shared_ptr<NodeObject>)> f =
-                    *(reinterpret_cast<
-                        std::function<void(std::shared_ptr<NodeObject>)>*>(fp));
-                f(decoded.createObject());
-            },
-            reinterpret_cast<void*>(&f));
-    }
-
-    int
-    getWriteLoad() override
-    {
-        return 0;
-    }
-
-    void
-    setDeletePath() override
-    {
-    }
-
-    void
-    verify() override
-    {
-    }
-
-    int
-    fdRequired() const override
-    {
-        return 3;
-    }
-};
-
-//------------------------------------------------------------------------------
-
-class SnugDBFactory : public Factory
-{
-public:
-    SnugDBFactory()
-    {
-        Manager::instance().insert(*this);
-    }
-
-    ~SnugDBFactory() override
-    {
-        Manager::instance().erase(*this);
-    }
-
-    std::string
-    getName() const override
-    {
-        return "SnugDB";
-    }
-
-    std::unique_ptr<Backend>
-    createInstance(
-        size_t keyBytes,
-        Section const& keyValues,
-        std::size_t burstSize,
-        Scheduler& scheduler,
-        beast::Journal journal) override
-    {
-        return std::make_unique<SnugDBBackend>(keyValues, scheduler, journal);
-    }
-
-    std::unique_ptr<Backend>
-    createInstance(
-        size_t keyBytes,
-        Section const& keyValues,
-        std::size_t burstSize,
-        Scheduler& scheduler,
-        nudb::context& context,
-        beast::Journal journal) override
-    {
-        return std::make_unique<SnugDBBackend>(keyValues, scheduler, journal);
-    }
-};
-
-static SnugDBFactory snugDBFactory;
-
-}  // namespace NodeStore
-}  // namespace ripple

src/ripple/nodestore/backend/snug.hpp

@@ -1,741 +0,0 @@
-#include <algorithm>
-#include <array>
-#include <fcntl.h>
-#include <memory>
-#include <mutex>
-#include <shared_mutex>
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <vector>
-
-#define MMAPFLAGS (PROT_READ | PROT_WRITE | MAP_NORESERVE), MAP_SHARED
-namespace snug {
-
-int
-compare_entries_reverse(const void* a, const void* b)
-{
-    const uint64_t* a_key = static_cast<const uint64_t*>(a);
-    const uint64_t* b_key = static_cast<const uint64_t*>(b);
-
-    // Unrolled comparison of 4 uint64_t values (4 * 8 = 32 bytes)
-    if (b_key[0] > a_key[0])
-        return 1;
-    if (b_key[0] < a_key[0])
-        return -1;
-
-    if (b_key[1] > a_key[1])
-        return 1;
-    if (b_key[1] < a_key[1])
-        return -1;
-
-    if (b_key[2] > a_key[2])
-        return 1;
-    if (b_key[2] < a_key[2])
-        return -1;
-
-    if (b_key[3] > a_key[3])
-        return 1;
-    if (b_key[3] < a_key[3])
-        return -1;
-
-    return 0;  // Keys are equal
-}
-
-class SnugDB
-{
-private:
-    static constexpr uint64_t SNUGSIZE =
-        256ull * 1024ull * 1024ull * 1024ull;  // 256 GiB
-    static constexpr uint64_t BIGSIZE =
-        10ull * 1024ull * 1024ull * 1024ull * 1024ull;  // 10 TiB
-
-    static constexpr size_t BUCKET_COUNT = 1048576;
-
-    std::unique_ptr<std::shared_mutex[]> mutexes =
-        std::make_unique<std::shared_mutex[]>(BUCKET_COUNT);
-
-    // each file snug.0 snug.1 ... is mmaped and the pointer
-    uint8_t* mapped_files[1024];
-    uint64_t mapped_files_count{0};
-
-    uint8_t* big_file;  // this file has 64kib blocks in it which are used
-                        // as an overflow for large blobs
-
-    std::mutex big_file_mutex;  // locked when incrementing the "next new block"
-                                // pointer
-
-    // only used when adding a new file
-    std::mutex mapped_files_count_mutex;
-
-    std::string const path;
-
-    // 0 = success
-    // 1 = could not open
-    // 2 = could not seek
-    // 3 = could not write at end of file
-    int
-    alloc_file(char const* fn, uint64_t size)
-    {
-        int fd = open(fn, O_WRONLY | O_CREAT | O_TRUNC, 0644);
-        if (fd < 0)
-            return 1;
-
-        // must be a multiple of bufsize
-
-        if (lseek(fd, size, SEEK_SET) == -1)
-        {
-            close(fd);
-            unlink(fn);
-            return 2;
-        }
-
-        if (write(fd, "", 1) != 1)
-        {
-            close(fd);
-            unlink(fn);
-            return 3;
-        }
-
-        close(fd);
-        return 0;
-    }
-
-    // 0 = file exists and is right size
-    int
-    check_file(char const* fn, uint64_t size)
-    {
-        struct stat st;
-        int file_exists = (stat(fn, &st) == 0);
-
-        if (!file_exists)
-            return 1;
-
-        if (st.st_size != size + 1)
-            return 2;
-
-        return 0;
-    }
-
-#define OFFSET(byte0, byte1, byte2)                                    \
-    (((((uint64_t)(byte0 & 0xFFU)) << 12) +                            \
-      (((uint64_t)(byte1 & 0xFFU)) << 4) + ((uint64_t)(byte2 & 0xFU))) \
-     << 18)
-
-    // check if 32 bytes are 0, which they will be for a zero entry
-#define IS_ZERO_ENTRY(x)                                             \
-    (*((uint64_t*)((x) + 0)) == 0 && *((uint64_t*)((x) + 8)) == 0 && \
-     *((uint64_t*)((x) + 16)) == 0 && *((uint64_t*)((x) + 24)) == 0)
-
-#define IS_ENTRY(x, y)                                       \
-    (*((uint64_t*)((x) + 0)) == *((uint64_t*)((y) + 0)) &&   \
-     *((uint64_t*)((x) + 8)) == *((uint64_t*)((y) + 8)) &&   \
-     *((uint64_t*)((x) + 16)) == *((uint64_t*)((y) + 16)) && \
-     *((uint64_t*)((x) + 24)) == *((uint64_t*)((y) + 24)))
-
-#define WRITE_KEY(x /* dst */, y /* src */, flags)           \
-    {                                                        \
-        *((uint64_t*)((x) + 0)) = *((uint64_t*)((y) + 0));   \
-        *((uint64_t*)((x) + 8)) = *((uint64_t*)((y) + 8));   \
-        *((uint64_t*)((x) + 16)) = *((uint64_t*)((y) + 16)); \
-        *((uint64_t*)((x) + 24)) = *((uint64_t*)((y) + 24)); \
-        *((uint64_t*)((x) + 32)) = flags;                    \
-    }
-
-    // if an entry exceeds 984 bytes then the overflow is written
-    // into the snug.big file in a linked list of 32kib blocks
-    // the first of those blocks is a control block
-
-    uint64_t
-    get_big_block()
-    {
-        std::unique_lock<std::mutex> lock(big_file_mutex);
-
-        uint64_t free_blocks = *((uint64_t*)(big_file + 8));
-        if (free_blocks == 0)
-        {
-            // no free blocks, allocate a new one
-            uint64_t next_block = *((uint64_t*)big_file);
-            // special edge case, first block ever allocated:
-            if (!next_block)
-                next_block += 32768;
-
-            *((uint64_t*)(big_file)) = next_block + 32768;
-
-            if (next_block + 32768 > BIGSIZE)
-                return 0;
-
-            return next_block;
-        }
-
-        // grab the nth one
-        uint8_t* offset = big_file + 16 + 8 * (free_blocks - 1);
-
-        // decrement free block counter
-        *(uint64_t*)(big_file + 8) -= 1;
-
-        return *((uint64_t*)offset);
-    }
-
-    void
-    unalloc_blocks(uint64_t next_block)
-    {
-        if (next_block != 0)
-        {
-            // scope the lock only if called with non-zero nextblock
-            std::unique_lock<std::mutex> lock(big_file_mutex);
-            do
-            {
-                uint64_t free_blocks = *((uint64_t*)(big_file + 8));
-
-                if (free_blocks >= 4095)
-                    break;
-
-                uint8_t* offset = big_file + 16 + 8 * free_blocks;
-
-                *((uint64_t*)offset) = next_block;
-
-                *((uint64_t*)(big_file + 8)) += 1;
-
-                uint8_t* big_ptr = big_file + next_block;
-                uint64_t previous = next_block;
-                next_block = *((uint64_t*)(big_file + next_block));
-
-                // clear the pointer on the old block
-                *((uint64_t*)(big_file + previous)) = 0;
-            } while (next_block != 0);
-        }
-    }
-
-    /*
-     * First big entry is control block:
-     * 0 - 7: The next free new block
-     * 8 - 15: The number of free blocks blow
-     * 16 - 23 [... repeating]: The next free unused block
-     */
-    /*
-     * Big entry format:
-     * 0   -     7: next block in chain, if any.
-     * 8  - 32767: payload
-     */
-
-    // return 0 = failure
-    //        > 0 = first block in the chain
-    uint64_t
-    write_big_entry_internal(uint8_t* data, ssize_t len, uint64_t next_block)
-    {
-        uint64_t first_block = 0;
-
-        uint64_t* last_block_ptr = 0;
-        do
-        {
-            // if next_block is populated we follow an existing pathway
-            // otherwise allocate a new block now
-
-            if (!next_block)
-                next_block = get_big_block();
-
-            if (!next_block)
-                return 0;
-
-            if (!first_block)
-                first_block = next_block;
-
-            if (last_block_ptr)
-                *last_block_ptr = next_block;
-
-            uint8_t* big_ptr = big_file + next_block;
-
-            // copy to the block
-            ssize_t to_write = len > 32760 ? 32760 : len;
-            memcpy(big_ptr + 8, data, to_write);
-
-            data += to_write;
-            len -= to_write;
-
-            next_block = *((uint64_t*)big_ptr);
-            last_block_ptr = (uint64_t*)big_ptr;
-        } while (len > 0);
-
-        // if there's a dangling chain we'll unallocate it
-        if (next_block != 0)
-            unalloc_blocks(next_block);
-
-        return first_block;
-    }
-
-    /*
-     * Entry format:
-     * 0    - 31: the 32 byte key
-     * 32   - 39: flags (high 4 bytes are flags, low 4 are size)
-     * 40 - 1023: data (up to 984 bytes)
-     */
-    // 0 = success
-    // 1 = bucket full
-    // 2 = big blocks full
-    int
-    write_entry_internal(
-        uint8_t* data,
-        uint8_t* key,
-        uint8_t* val,
-        uint32_t len)
-    {
-        // find the entry
-        uint64_t offset = OFFSET(key[0], key[1], (key[2] >> 4));
-
-        // lock the bucket for writing
-        std::unique_lock<std::shared_mutex> lock(mutexes[offset >> 18]);
-
-        uint8_t* start = data + offset;
-        for (int i = 0; i < 256 * 1024; i += 1024)
-        {
-            bool const found = IS_ENTRY(start + i, key);
-            if (!found && !IS_ZERO_ENTRY(start + i))
-                continue;
-
-            // special edge case: the key doesn't exist and they're trying to
-            // delete it
-            if (!found && len == 0)
-                return 0;
-
-            // read flags
-            uint64_t flags = *((uint64_t*)(start + i + 32));
-
-            // big entries are tricky
-            bool const old_big = (flags >> 32) != 0;
-            bool const new_big = len > 984;
-
-            if (new_big)
-            {
-                // write_big_entry_internal(uint8_t* data, ssize_t len, uint64_t
-                // next_block)
-                uint64_t first_block = write_big_entry_internal(
-                    val + 984, len - 984, (old_big ? (flags >> 32) : 0));
-
-                if (first_block == 0)  // error state
-                {
-                    if (old_big)
-                        unalloc_blocks(flags >> 32);
-
-                    return 2;
-                }
-
-                flags = (first_block << 32) + len;
-            }
-            else if (old_big)  // big blocks exist but new value is small
-            {
-                // unallocate the old chain
-                unalloc_blocks(flags >> 32);
-            }
-
-            if (!new_big)
-                flags = len;
-
-            if (len == 0)
-            {
-                // deletion requests are written as zero keys
-                memset(start + i, 0, 1024);
-            }
-            else
-            {
-                /// write entry
-                WRITE_KEY(start + i, key, flags);
-                memcpy(start + i + 40, val, (len > 984 ? 984 : len));
-            }
-
-            // sort the bucket backwards so 0's appear at the end
-            qsort(start, 256, 1024, compare_entries_reverse);
-
-            return 0;
-        }
-
-        /// file (bucket) full
-        return 1;
-    }
-
-    // out_len carries the length of the output buffer when calling and is
-    // replaced with the length of the data found when returning
-    int
-    read_entry_internal(
-        uint8_t* data,
-        uint8_t* key,
-        uint8_t* val_out,
-        uint64_t* out_len)
-    {
-        uint64_t buf_len = *out_len;
-
-        // find the entry
-        uint64_t offset = OFFSET(key[0], key[1], (key[2] >> 4));
-        uint8_t* start = data + offset;
-
-        // lock the bucket for reading
-        std::shared_lock<std::shared_mutex> lock(mutexes[offset >> 18]);
-
-        for (int i = 0; i < 256 * 1024; i += 1024)
-        {
-            if (IS_ZERO_ENTRY(start + i))
-                return 1;
-
-            if (!IS_ENTRY(start + i, key))
-                continue;
-
-            // read out the value
-
-            uint64_t flags = *((uint64_t*)(start + i + 32));
-
-            uint32_t size = flags & 0xFFFFFFFFUL;
-            uint64_t next_block = flags >> 32;
-
-            if (size > buf_len)
-                return 2;
-
-            *out_len = size;
-
-            size_t to_read = size > 984 ? 984 : size;
-            memcpy(val_out, start + i + 40, to_read);
-
-            val_out += to_read;
-            size -= to_read;
-
-            // big block read logic
-            while (size > 0)
-            {
-                // follow big block pointers
-                if (!next_block)
-                {
-                    printf("End while size=%d\n", size);
-                    return 3;
-                }
-
-                uint8_t* big_ptr = big_file + next_block;
-                to_read = size > 32760 ? 32760 : size;
-                memcpy(val_out, big_ptr + 8, to_read);
-
-                val_out += to_read;
-                size -= to_read;
-
-                next_block = *((uint64_t*)big_ptr);
-            }
-
-            return 0;
-        }
-
-        return 1;
-    }
-
-    void
-    setup()
-    {
-        struct stat path_stat;
-
-        if (stat(path.c_str(), &path_stat) != 0)
-            throw std::runtime_error(
-                "Error checking path: " + path + " - " +
-                std::string(strerror(errno)));
-
-        if (!S_ISDIR(path_stat.st_mode))
-            throw std::runtime_error("Path is not a directory: " + path);
-
-        if (access(path.c_str(), R_OK | W_OK | X_OK) != 0)
-            throw std::runtime_error(
-                "Insufficient permissions for path: " + path);
-
-        // Search for existing snug files sequentially
-        std::vector<std::string> snug_files;
-        for (int file_index = 0; file_index < 1024; ++file_index)
-        {
-            std::string filename = "snug." + std::to_string(file_index);
-            std::string full_path = path + "/" + filename;
-
-            if (access(full_path.c_str(), F_OK) != 0)
-                break;
-
-            snug_files.push_back(filename);
-        }
-
-        // If no files found, create snug.0
-        if (snug_files.empty())
-        {
-            std::string new_file = path + "/snug.0";
-            int result = alloc_file(new_file.c_str(), SNUGSIZE);
-            if (result != 0)
-                throw std::runtime_error(
-                    "Failed to create initial file: " + new_file);
-            snug_files.push_back("snug.0");
-        }
-
-        // Memory map all files
-        for (const auto& file : snug_files)
-        {
-            std::string full_path = path + "/" + file;
-            if (check_file(full_path.c_str(), SNUGSIZE) != 0)
-                throw std::runtime_error("File was the wrong size: " + file);
-
-            int fd = open(full_path.c_str(), O_RDWR);
-            if (fd == -1)
-                throw std::runtime_error("Unable to open file: " + full_path);
-
-            struct stat file_stat;
-            if (fstat(fd, &file_stat) == -1)
-            {
-                close(fd);
-                throw std::runtime_error(
-                    "Unable to get file stats: " + full_path);
-            }
-
-            void* mapped = mmap(nullptr, file_stat.st_size, MMAPFLAGS, fd, 0);
-            close(fd);  // Can close fd after mmap
-
-            if (mapped == MAP_FAILED)
-                throw std::runtime_error("Unable to mmap file: " + full_path);
-
-            mapped_files[mapped_files_count++] = static_cast<uint8_t*>(mapped);
-        }
-
-        // create and map snug.big overflow file
-        {
-            std::string new_file = path + "/snug.big";
-            if (check_file(new_file.c_str(), BIGSIZE) != 0)
-            {
-                int result = alloc_file(new_file.c_str(), BIGSIZE);
-                if (result != 0)
-                    throw std::runtime_error(
-                        "Failed to create initial file: " + new_file);
-            }
-
-            int fd = open(new_file.c_str(), O_RDWR);
-            if (fd == -1)
-                throw std::runtime_error("Unable to open file: " + new_file);
-
-            struct stat file_stat;
-            if (fstat(fd, &file_stat) == -1)
-            {
-                close(fd);
-                throw std::runtime_error(
-                    "Unable to get file stats: " + new_file);
-            }
-
-            void* mapped = mmap(nullptr, file_stat.st_size, MMAPFLAGS, fd, 0);
-            close(fd);  // Can close fd after mmap
-
-            if (mapped == MAP_FAILED)
-                throw std::runtime_error("Unable to mmap file: " + new_file);
-
-            big_file = static_cast<uint8_t*>(mapped);
-        }
-    }
-
-public:
-    SnugDB(std::string path_) : path(path_)
-    {
-        setup();
-    }
-
-    ~SnugDB()
-    {
-        // Unmap all files in destructor
-        // RH TODO: consider lock here
-        for (int i = 0; i < mapped_files_count; ++i)
-            munmap(mapped_files[i], SNUGSIZE);
-
-        // unmap the big file
-        munmap(big_file, BIGSIZE);
-    }
-
-    int
-    write_entry(uint8_t* key, uint8_t* val, ssize_t len)
-    {
-        for (size_t i = 0; i < mapped_files_count; ++i)
-        {
-            int result = write_entry_internal(mapped_files[i], key, val, len);
-            if (result == 0)
-                return 0;
-
-            if (result != 1)  // only bucket full falls through
-                return result;
-        }
-
-        // All existing files are full, allocate a new one
-        {
-            // acquire the mutex
-            const std::lock_guard<std::mutex> lock(mapped_files_count_mutex);
-
-            std::string new_file =
-                path + "/snug." + std::to_string(mapped_files_count);
-            int alloc_result = alloc_file(new_file.c_str(), SNUGSIZE);
-            if (alloc_result != 0)
-                return alloc_result +
-                    10;  // Return error code from alloc_file if it fails (+10)
-
-            int fd = open(new_file.c_str(), O_RDWR);
-            if (fd == -1)
-                return 1;  // Return 1 for open failure
-
-            struct stat file_stat;
-            if (fstat(fd, &file_stat) == -1)
-            {
-                close(fd);
-                return 2;  // Return 2 for fstat failure
-            }
-
-            void* mapped = mmap(
-                nullptr,
-                file_stat.st_size,
-                PROT_READ | PROT_WRITE,
-                MAP_SHARED,
-                fd,
-                0);
-            close(fd);  // Can close fd after mmap
-
-            if (mapped == MAP_FAILED)
-                return 3;  // Return 3 for mmap failure
-
-            // add the new file to the map, and increment the counter
-            mapped_files[mapped_files_count] = static_cast<uint8_t*>(mapped);
-
-            // this is the last possible thing done
-            mapped_files_count++;
-        }
-
-        // finally write the entry
-        // RH TODO: consider adding a recursion guard here
-        return write_entry(key, val, len);
-    }
-
-    int
-    read_entry(uint8_t* key, uint8_t* val_out, uint64_t* out_len_orig)
-    {
-        for (size_t i = 0; i < mapped_files_count; ++i)
-        {
-            uint64_t out_len = *out_len_orig;
-
-            int result =
-                read_entry_internal(mapped_files[i], key, val_out, &out_len);
-
-            if (result == 0)
-            {
-                *out_len_orig = out_len;
-                return 0;  // Entry found and read successfully
-            }
-
-            if (result == 2)
-                return 2;  // Output buffer too small
-        }
-
-        // Entry not found in any file
-        return 1;
-    }
-
-    void
-    visit_all(
-        void (*f)(uint8_t*, uint8_t*, uint64_t, void* /*opaque caller val*/),
-        void* opaque)
-    {
-        // to visit all we only need to check snug.0 to begin with
-        // we go to the first bucket
-        // if we find no entries there we go to the next bucket
-        // if we find entries there then we need to count them,
-        // if we find 256 entries there then we go to snug.1 and so on until we
-        // run out we merge sort the entries into a list for the visit
-
-        for (uint64_t bucket = 0; bucket < BUCKET_COUNT; ++bucket)
-        {
-            // acquire the bucket lock
-            std::shared_lock<std::shared_mutex> lock(mutexes[bucket]);
-
-            // check the bucket
-            uint8_t* ptr = mapped_files[0] + (bucket << 18);
-
-            if (*((uint64_t*)(ptr + 32)) == 0)
-                continue;
-
-            // if (IS_ZERO_ENTRY(ptr))
-            //    continue;
-
-            // live bucket, collect entries
-            std::vector<uint8_t*> entries;
-            {
-                // need to acquire the mutex to prevent a race condition
-                // where a new file is being added while we're searching
-                const std::lock_guard<std::mutex> lock(
-                    mapped_files_count_mutex);
-
-                // preallocate worst case scenario, RIP memory
-                entries.reserve(mapped_files_count * 256);
-
-                for (int i = 0; i < mapped_files_count; ++i)
-                {
-                    uint8_t* ptr = mapped_files[i] + (bucket << 18);
-                    for (int entry_count = 0;
-                         !IS_ZERO_ENTRY(ptr) && entry_count < 256;
-                         ++entry_count, ptr += 1024)
-                        entries.push_back(ptr);
-                }
-            }
-
-            if (entries.empty())
-                continue;
-
-            // sort the entries
-            std::sort(
-                entries.begin(),
-                entries.end(),
-                [](const uint8_t* a, const uint8_t* b) {
-                    return memcmp(a, b, 32) < 0;
-                });
-
-            for (auto e : entries)
-            {
-                // visitation
-                uint8_t* entry = &e[0];
-                uint64_t flags = *((uint64_t*)(entry + 32));
-                uint64_t next_block = flags >> 32;
-                uint64_t size = flags & 0xFFFFFFFFULL;
-
-                if (size <= 984)
-                {
-                    f(entry, entry + 40, size, opaque);
-                    continue;
-                }
-
-                // copy big entry to a buffer
-                std::unique_ptr<uint8_t[]> copybuf =
-                    std::make_unique<uint8_t[]>(size);
-
-                uint8_t* data = &(copybuf[0]);
-                memcpy(data, entry + 40, 984);
-
-                data += 984;
-                size -= 984;
-
-                // big block read logic
-                while (size > 0)
-                {
-                    // follow big block pointers
-                    if (!next_block)
-                    {
-                        printf("End while size=%lu\n", size);
-                        return;
-                    }
-
-                    uint8_t* big_ptr = big_file + next_block;
-                    uint64_t to_read = size > 32760 ? 32760 : size;
-                    memcpy(data, big_ptr + 8, to_read);
-
-                    data += to_read;
-                    size -= to_read;
-
-                    next_block = *((uint64_t*)big_ptr);
-                }
-
-                f(entry, data, (flags & 0xFFFFFFFFULL), opaque);
-            }
-        }
-    }
-};
-
-}  // namespace snug

src/ripple/protocol/Email.h

@@ -0,0 +1,493 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <regex>
+#include <sstream>
+#include <stdexcept>
+
+// make this typedef to keep dkim happy
+typedef int _Bool;
+#include <opendkim/dkim.h>
+
+using namespace ripple;
+namespace Email
+{
+
+    enum EmailType : uint8_t
+    {
+        INVALID = 0,
+        REMIT = 1,
+        REKEY = 2
+    };
+
+    struct EmailDetails
+    {
+        std::string domain; // from address domain
+        std::string dkimDomain; // dkim signature domain
+
+        AccountID from;
+        std::string fromEmail;
+
+        std::optional<std::string> toEmail;
+        std::optional<AccountID> to;
+
+        EmailType emailType { EmailType::INVALID };
+        std::optional<STAmount> amount; // only valid if REMIT type
+        std::optional<AccountID> rekey; // only valid if REKEY type
+    };
+
+    class OpenDKIM
+    {
+    private:
+        DKIM_STAT status;
+    public:
+        DKIM_LIB* dkim_lib;
+        DKIM* dkim;
+
+        bool sane()
+        {
+            return !!dkim_lib && !!dkim;
+        }
+
+        OpenDKIM()
+        { 
+            // do nothing
+        }
+
+        // setup is in its own function not the constructor to make failure graceful
+        bool setup(beast::Journal& j)
+        {
+            dkim_lib = dkim_init(nullptr, nullptr);
+            if (!dkim_lib)
+            {
+                JLOG(j.warn()) << "EmailAmendment: Failed to init dkim_lib.";
+                return false;
+            }
+
+            DKIM_STAT status;
+            DKIM* dkim = dkim_verify(dkim_lib, (uint8_t const*)"id", nullptr, &status);
+            if (!dkim_lib)
+            {
+                JLOG(j.warn()) << "EmailAmendment: Failed to init dkim_verify.";
+                return false;
+            }
+
+            return true;
+        }
+        
+        ~OpenDKIM()
+        {
+            if (dkim)
+            {
+                dkim_free(dkim);
+                dkim = nullptr;
+            }
+
+            if (dkim_lib)
+            {
+                dkim_close(dkim_lib);
+                dkim_lib = nullptr;
+            }
+        }
+    };
+
+    inline
+    std::optional<std::pair<std::string /* canonical email addr */, std::string /* canonical domain */>>
+    canonicalizeEmailAddress(const std::string& rawEmailAddr)
+    {
+        if (rawEmailAddr.empty())
+            return {};
+
+        // trim
+        auto start = std::find_if_not(str.begin(), str.end(), ::isspace);
+        auto end = std::find_if_not(str.rbegin(), str.rend(), ::isspace).base();
+
+        if (end >= start)
+            return {};
+
+        std::email = std::string(start, end);
+       
+        if (email.empty())
+            return {};
+        
+        // to lower
+        std::transform(email.begin(), email.end(), email.begin(), ::tolower);
+
+        // find the @
+        size_t atPos = email.find('@');
+        if (atPos == std::string::npos || atPos == email.size() - 1)
+            return {};
+
+        std::string localPart = email.substr(0, atPos);
+        std::string domain = email.substr(atPos + 1);
+
+        if (domain.empty() || localPart.empty())
+            return {};
+        
+        // ensure there's only one @
+        if (domain.find('@') != std::string::npos)
+            return {};
+        
+        // canonicalize domain part
+        {
+            std::string result = domain;
+            std::transform(result.begin(), result.end(), result.begin(), ::tolower);
+            while (!result.empty() && result.back() == '.')
+                result.pop_back();
+
+            doamin = result;
+        }        
+        
+        if (domain.empty())
+            return {};
+
+        // canonicalize local part
+        {
+            std::string part = localPart;
+            part.erase(std::remove_if(
+                        part.begin(), part.end(), 
+                        [](char c) { return c == '(' || c == ')' || std::isspace(c); }), part.end());
+
+            size_t plusPos = part.find('+');
+            if (plusPos != std::string::npos)
+                part = part.substr(0, plusPos);
+
+            while (!part.empty() && part.back() == '.')
+                part.pop_back();
+
+            // gmail ignores dots
+            if (domain == "gmail.com")
+                part.erase(std::remove(part.begin(), part.end(), '.'), part.end());
+
+            localPart = part;
+        }
+
+        if (localPart.empty())
+            return {};
+
+        return {{localPart + "@" + domain, domain}};
+    };
+
+    // Warning: must supply already canonicalzied email
+    inline
+    std::optional<AccountID>
+    emailToAccountID(const std::string& canonicalEmail)
+    {
+        uint8_t innerHash[SHA512_DIGEST_LENGTH + 4];
+        SHA512_CTX sha512;
+        SHA512_Init(&sha512);
+        SHA512_Update(&sha512, canonicalEmail.c_str(), canonicalEmail.size());
+        SHA512_Final(innerHash + 4, &sha512);
+        innerHash[0] = 0xEEU;
+        innerHash[1] = 0xEEU;
+        innerHash[2] = 0xFFU;
+        innerHash[3] = 0xFFU;
+        {
+            uint8_t hash[SHA512_DIGEST_LENGTH];
+            SHA512_CTX sha512;
+            SHA512_Init(&sha512);
+            SHA512_Update(&sha512, innerHash, sizeof(innerHash));
+            SHA512_Final(hash, &sha512);
+
+            return AccountID::fromVoid((void*)hash);
+        }
+    }
+
+
+    inline
+    std::optional<EmailDetails>
+    parseEmail(std::string const& rawEmail, beast::Journal& j)
+    {
+        EmailDetails out;
+
+        // parse email into headers and body
+        std::vector<std::string> headers;
+        std::string body;
+        {
+            std::istringstream stream(rawEmail);
+            std::string line;
+
+            while (std::getline(stream, line))
+            {
+                if (line.empty() || line == "\r")
+                    break;
+
+                // Handle header line continuations
+                while (stream.peek() == ' ' || stream.peek() == '\t') {
+                    std::string continuation;
+                    std::getline(stream, continuation);
+                    line += '\n' + continuation;
+                }
+                if (!line.empty()) {
+                    headers.push_back(line.substr(0, line.size() - (line.back() == '\r' ? 1 : 0)));
+                }
+            }
+
+            std::ostringstream body_stream;
+            while (std::getline(stream, line))
+                body_stream << line << "\n";
+            body = body_stream.str();
+        }
+
+
+        // find the from address, canonicalize it and extract the domain
+        bool foundFrom = false;
+        bool foundTo = false;
+        {
+            static const std::regex
+                from_regex(R"(^From:\s*(?:.*<)?([^<>\s]+@[^<>\s]+)(?:>)?)", std::regex::icase);
+
+            static const std::regex
+                to_regex(R"(^To:\s*(?:.*<)?([^<>\s]+@[^<>\s]+)(?:>)?)", std::regex::icase);
+
+            for (const auto& header : headers)
+            {
+                if (foundFrom && foundTo)
+                    break;
+
+                std::smatch match;
+                if (!foundFrom && std::regex_search(header, match, from_regex) && match.size() > 1)
+                {
+                    auto canon = canonicalizeEmailAddress(match[1].str());
+                    if (!canon)
+                    {
+                        JLOG(j.warn())
+                            << "EmailAmendment: Cannot parse From address: `"
+                            << match[1].str() << "`";
+                        return {};
+                    }
+
+                    out.fromEmail = canon->first;
+                    out.domain = canon->second;
+                    out.from = emailToAccountID(out.fromEmail);
+                    foundFrom = true;
+
+                    continue;
+                }
+
+                if (std::regex_search(header, match, to_regex) && match.size() > 1)
+                {
+                    auto canon = canonicalizeEmailAddress(match[1].str());
+                    if (!canon)
+                    {
+                        JLOG(j.warn())
+                            << "EmailAmendment: Cannot parse To address: `"
+                            << match[1].str() << "`";
+                        return {};
+                    }
+
+                    out.toEmail = canon->first;
+                    out.to = emailToAccountID(out.toEmail);
+
+                    foundTo = true;
+                    continue;
+                }
+            }
+
+            if (!foundFrom)
+            {
+                JLOG(j.warn()) << "EmailAmendment: No From address present in email.";
+                return {};
+            }
+        }
+
+        // execution to here means we have:
+        //  1. Parsed headers and body
+        //  2. Found a from address and canonicalzied it
+        //  3. Potentially found a to address and canonicalized it.
+
+        // Find instructions
+        {
+            static const std::regex
+                remitPattern(R"(^REMIT (\d+(?:\.\d+)?) ([A-Z]{3})(?:/([r][a-zA-Z0-9]{24,34}))?)");
+            
+            static const std::regex
+                rekeyPattern(R"(^REKEY ([r][a-zA-Z0-9]{24,34}))");
+
+            std::istringstream stream(body);
+            std::string line;
+
+            out.emailType = EmailType::INVALID;
+
+            while (std::getline(stream, line, '\n'))
+            {
+                if (!line.empty() && line.back() == '\r')
+                    line.pop_back(); // Remove '\r' if present
+
+                std::smatch match;
+                if (std::regex_match(line, match, remitPattern))
+                {
+                    try
+                    {
+                        Currency cur;
+                        if (!to_currency(cur, match[2]))
+                        {
+                            JLOG(j.warn()) << "EmailAmendment: Could not parse currency code.";
+                            return {};
+                        }
+
+
+                        AccountID issuer = noAccount();
+                        if (match[3].matched)
+                        {
+                            if (isXRP(cur))
+                            {
+                                JLOG(j.warn()) << "EmailAmendment: Native currency cannot specify issuer.";
+                                return {};
+                            }
+
+                            issuer = decodeBase58Token(match[3], TokenType::AccountID);
+                            if (issuer.empty())
+                            {
+                                JLOG(j.warn()) << "EmailAmendment: Could not parse issuer address.";
+                                return {};
+                            }
+                        }
+
+                        out.amount = amountFromString({cur, issuer}, match[1]);
+
+                    }
+                    catch (std::exception const& e)
+                    {
+                        JLOG(j.warn()) << "EmailAmendment: Exception while parsing REMIT. " << e.what();
+                        return {};
+                    }
+
+                    out.emailType = EmailType::REMIT;
+                    break;
+                }
+
+                if (std::regex_match(line, match, rekeyPattern))
+                {
+                    AccountID rekey = decodeBase58Token(match[1], TokenType::AccountID);
+                    if (rekey.empty())
+                    {
+                        JLOG(j.warn()) << "EmailAmendment: Could not parse rekey address.";
+                        return {};
+                    }
+
+                    out.rekey = rekey;                
+                    out.emailType = EmailType::REKEY;
+                    break;
+                }
+            }
+
+            if (out.emailType == EmailType::INVALID)
+            {
+                JLOG(j.warn()) << "EmailAmendment: Invalid email type, could not find REMIT or REKEY.";
+                return{};
+            }
+        }    
+
+
+        // perform DKIM checks...
+        // to do this we will use OpenDKIM, and manage it with a smart pointer to prevent
+        // any leaks from uncommon exit pathways
+
+        std::unique<OpenDKIM> odkim;
+
+        // perform setup
+        if (!odkim->setup(j) || !odkim->sane())
+            return {};
+
+        // when odkim goes out of scope it will call the C-apis to destroy the dkim instances
+
+        DKIM_STAT status;
+        DKIM_LIB* dkim_lib = odkim->dkim_lib;
+        DKIM* dkim = odkim->dkim;
+
+        // feed opendkim all headers
+        {
+            for (const auto& header : headers)
+            {
+                status = dkim_header(dkim, (uint8_t*)header.c_str(), header.length());
+                if (status != DKIM_STAT_OK)
+                {
+                    JLOG(j.warn())
+                        << "EmailAmendment: OpenDKIM Failed to process header: "
+                        << dkim_geterror(dkim);
+                    return {};
+                }
+            }
+
+            status = dkim_eoh(dkim);
+            if (status != DKIM_STAT_OK)
+            {
+                JLOG(j.warn())
+                    << "EmailAmendment: OpenDKIM Failed to send end-of-headers"l
+                return {};
+            }
+        }
+
+        // feed opendkim email body
+        {
+            status = dkim_body(dkim, (uint8_t*)body.c_str(), body.size());
+            if (status != DKIM_STAT_OK)
+            {
+                JLOG(j.warn())
+                    << "EmailAmendment: OpenDKIM Failed to process body: " 
+                    << dkim_geterror(dkim);
+                return {};
+            }
+
+            _Bool testkey;
+            status = dkim_eom(dkim, &testkey);
+            if (status != DKIM_STAT_OK)
+            {
+                JLOG(j.warn())
+                    << "EmailAmendment: OpenDKIM end-of-message error: "
+                    << dkim_geterror(dkim);
+                return {};
+            }
+
+            DKIM_SIGINFO* sig = dkim_getsignature(dkim);
+            if (!sig)
+            {
+                JLOG(j.warn())
+                   << "EmailAmendment: No DKIM signature found";
+                return {};
+            }
+
+            if (dkim_sig_getbh(sig) != DKIM_SIGBH_MATCH)
+            {
+                JLOG(j.warn())
+                    << "EmailAmendment: DKIM body hash mismatch";
+                return {};
+            }
+
+
+            DKIM_SIGINFO* sig = dkim_getsignature(dkim);
+            if (!sig)
+            {
+                JLOG(j.warn())
+                    << "EmailAmendment: DKIM signature not found.";
+                return {};
+            }
+
+            out.dkimDomain = 
+                std::string(reinterpret_cast<char const*>(
+                            reinterpret_cast<void const*>(dkim_sig_getdomain(sig))));
+
+            if (out.dkimDomain.empty())
+            {
+                JLOG(j.warn())
+                    << "EmailAmendment: DKIM signature domain empty.";
+                return {};
+            }
+
+            // RH TODO: decide whether to relax this or not
+            // strict domain check
+            if (out.dkimDomain != out.domain)
+            {
+                JLOG(j.warn())
+                    << "EmailAmendment: DKIM domain does not match From address domain.";
+                return {};
+            }
+        }
+
+        // execution to here means all checks passed and the instruction was correctly parsed
+        return out;
+    }
+
+
+}

src/ripple/protocol/Feature.h

@@ -74,7 +74,7 @@ namespace detail {
 // Feature.cpp. Because it's only used to reserve storage, and determine how
 // large to make the FeatureBitset, it MAY be larger. It MUST NOT be less than
 // the actual number of amendments. A LogicError on startup will verify this.
-static constexpr std::size_t numFeatures = 70;
+static constexpr std::size_t numFeatures = 71;
 
 /** Amendments that this server supports and the default voting behavior.
    Whether they are enabled depends on the Rules defined in the validated
@@ -358,6 +358,7 @@ extern uint256 const fixXahauV2;
 extern uint256 const featureRemit;
 extern uint256 const featureZeroB2M;
 extern uint256 const fixNSDelete;
+extern uint256 const featureEmail;
 
 }  // namespace ripple
 

src/ripple/protocol/STTx.h

@@ -30,6 +30,7 @@
 #include <ripple/protocol/TxFormats.h>
 #include <boost/container/flat_set.hpp>
 #include <functional>
+#include <ripple/protocol/Email.h>
 
 namespace ripple {
 

src/ripple/protocol/TxFlags.h

@@ -57,8 +57,9 @@ namespace ripple {
 // Universal Transaction flags:
 enum UniversalFlags : uint32_t {
     tfFullyCanonicalSig = 0x80000000,
+    tfEmailSig          = 0x40000000,
 };
-constexpr std::uint32_t tfUniversal                        = tfFullyCanonicalSig;
+constexpr std::uint32_t tfUniversal                        = tfFullyCanonicalSig | tfEmailSig;
 constexpr std::uint32_t tfUniversalMask                    = ~tfUniversal;
 
 // AccountSet flags:

src/ripple/protocol/impl/Feature.cpp

@@ -464,6 +464,7 @@ REGISTER_FIX    (fixXahauV2,                    Supported::yes, VoteBehavior::De
 REGISTER_FEATURE(Remit,                         Supported::yes, VoteBehavior::DefaultNo);
 REGISTER_FEATURE(ZeroB2M,                       Supported::yes, VoteBehavior::DefaultNo);
 REGISTER_FIX    (fixNSDelete,                   Supported::yes, VoteBehavior::DefaultNo);
+REGISTER_FEATURE(Email,                         Supported::yes, VoteBehavior::DefaultNo);
 
 // The following amendments are obsolete, but must remain supported
 // because they could potentially get enabled.

src/ripple/protocol/impl/STTx.cpp

@@ -304,9 +304,60 @@ STTx::checkSingleSign(RequireFullyCanonicalSig requireCanonicalSig) const
     bool const isWildcardNetwork =
         isFieldPresent(sfNetworkID) && getFieldU32(sfNetworkID) == 65535;
 
+    // email signature flag signals that the txn is authorized
+    // only by the presence of a DKIM signed email in memos[0] 
+
+    bool const isEmailSig =
+        getFlags() & tfEmailSig;
+
+
     bool validSig = false;
+    do
     try
     {
+    
+        if (isEmailSig)
+        {
+    
+            if (!isFieldPresent(sfMemos))
+                break;
+
+            auto const& memos = st.getFieldArray(sfMemos);
+            auto const& memo = memos[0];
+            auto memoObj = dynamic_cast<STObject const*>(&memo);
+            if (!memoObj || (memoObj->getFName() != sfMemo))
+                break;
+
+            bool emailValid = false;
+
+            for (auto const& memoElement : *memoObj)
+            {
+                auto const& name = memoElement.getFName();
+
+                if (name != sfMemoType && name != sfMemoData &&
+                    name != sfMemoFormat)
+                    break;
+
+                // The raw data is stored as hex-octets, which we want to decode.
+                std::optional<Blob> optData = strUnHex(memoElement.getText());
+
+                if (!optData)
+                    break;
+
+                if (name != sfMemoData)
+                    continue;
+
+                std::string const emailContent((char const*)(optData->data()), optData->size());
+
+
+                // RH UPTO
+
+
+            }
+        }
+            
+        }
+
         bool const fullyCanonical = (getFlags() & tfFullyCanonicalSig) ||
             (requireCanonicalSig == RequireFullyCanonicalSig::yes);
 
@@ -328,7 +379,8 @@ STTx::checkSingleSign(RequireFullyCanonicalSig requireCanonicalSig) const
     {
         // Assume it was a signature failure.
         validSig = false;
-    }
+    } while (0);
+
     if (validSig == false)
         return Unexpected("Invalid signature.");
     // Signature was verified.