root/tools/testing/selftests/net/tcp_mmap.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2018 Google Inc.
 * Author: Eric Dumazet (edumazet@google.com)
 *
 * Reference program demonstrating tcp mmap() usage,
 * and SO_RCVLOWAT hints for receiver.
 *
 * Note : NIC with header split is needed to use mmap() on TCP :
 * Each incoming frame must be a multiple of PAGE_SIZE bytes of TCP payload.
 *
 * How to use on loopback interface :
 *
 *  ifconfig lo mtu 61512  # 15*4096 + 40 (ipv6 header) + 32 (TCP with TS option header)
 *  tcp_mmap -s -z &
 *  tcp_mmap -H ::1 -z
 *
 *  Or leave default lo mtu, but use -M option to set TCP_MAXSEG option to (4096 + 12)
 *      (4096 : page size on x86, 12: TCP TS option length)
 *  tcp_mmap -s -z -M $((4096+12)) &
 *  tcp_mmap -H ::1 -z -M $((4096+12))
 *
 * Note: -z option on sender uses MSG_ZEROCOPY, which forces a copy when packets go through loopback interface.
 *       We might use sendfile() instead, but really this test program is about mmap(), for receivers ;)
 *
 * $ ./tcp_mmap -s &                                 # Without mmap()
 * $ for i in {1..4}; do ./tcp_mmap -H ::1 -z ; done
 * received 32768 MB (0 % mmap'ed) in 14.1157 s, 19.4732 Gbit
 *   cpu usage user:0.057 sys:7.815, 240.234 usec per MB, 65531 c-switches
 * received 32768 MB (0 % mmap'ed) in 14.6833 s, 18.7204 Gbit
 *  cpu usage user:0.043 sys:8.103, 248.596 usec per MB, 65524 c-switches
 * received 32768 MB (0 % mmap'ed) in 11.143 s, 24.6682 Gbit
 *   cpu usage user:0.044 sys:6.576, 202.026 usec per MB, 65519 c-switches
 * received 32768 MB (0 % mmap'ed) in 14.9056 s, 18.4413 Gbit
 *   cpu usage user:0.036 sys:8.193, 251.129 usec per MB, 65530 c-switches
 * $ kill %1   # kill tcp_mmap server
 *
 * $ ./tcp_mmap -s -z &                              # With mmap()
 * $ for i in {1..4}; do ./tcp_mmap -H ::1 -z ; done
 * received 32768 MB (99.9939 % mmap'ed) in 6.73792 s, 40.7956 Gbit
 *   cpu usage user:0.045 sys:2.827, 87.6465 usec per MB, 65532 c-switches
 * received 32768 MB (99.9939 % mmap'ed) in 7.26732 s, 37.8238 Gbit
 *   cpu usage user:0.037 sys:3.087, 95.3369 usec per MB, 65532 c-switches
 * received 32768 MB (99.9939 % mmap'ed) in 7.61661 s, 36.0893 Gbit
 *   cpu usage user:0.046 sys:3.559, 110.016 usec per MB, 65529 c-switches
 * received 32768 MB (99.9939 % mmap'ed) in 7.43764 s, 36.9577 Gbit
 *   cpu usage user:0.035 sys:3.467, 106.873 usec per MB, 65530 c-switches
 */
#define _GNU_SOURCE
#include <pthread.h>
#include <sys/types.h>
#include <fcntl.h>
#include <error.h>
#include <sys/socket.h>
#include <sys/mman.h>
#include <sys/resource.h>
#include <unistd.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <time.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <poll.h>
#include <linux/tcp.h>
#include <assert.h>
#include <openssl/pem.h>

#ifndef MSG_ZEROCOPY
#define MSG_ZEROCOPY    0x4000000
#endif

#ifndef min
#define min(a, b)  ((a) < (b) ? (a) : (b))
#endif

#define FILE_SZ (1ULL << 35)
static int cfg_family = AF_INET6;
static socklen_t cfg_alen = sizeof(struct sockaddr_in6);
static int cfg_port = 8787;

static int rcvbuf; /* Default: autotuning.  Can be set with -r <integer> option */
static int sndbuf; /* Default: autotuning.  Can be set with -w <integer> option */
static int zflg; /* zero copy option. (MSG_ZEROCOPY for sender, mmap() for receiver */
static int xflg; /* hash received data (simple xor) (-h option) */
static int keepflag; /* -k option: receiver shall keep all received file in memory (no munmap() calls) */
static int integrity; /* -i option: sender and receiver compute sha256 over the data.*/

static size_t chunk_size  = 512*1024;

static size_t map_align;

unsigned long htotal;
unsigned int digest_len;

static inline void prefetch(const void *x)
{
#if defined(__x86_64__)
        asm volatile("prefetcht0 %P0" : : "m" (*(const char *)x));
#endif
}

void hash_zone(void *zone, unsigned int length)
{
        unsigned long temp = htotal;

        while (length >= 8*sizeof(long)) {
                prefetch(zone + 384);
                temp ^= *(unsigned long *)zone;
                temp ^= *(unsigned long *)(zone + sizeof(long));
                temp ^= *(unsigned long *)(zone + 2*sizeof(long));
                temp ^= *(unsigned long *)(zone + 3*sizeof(long));
                temp ^= *(unsigned long *)(zone + 4*sizeof(long));
                temp ^= *(unsigned long *)(zone + 5*sizeof(long));
                temp ^= *(unsigned long *)(zone + 6*sizeof(long));
                temp ^= *(unsigned long *)(zone + 7*sizeof(long));
                zone += 8*sizeof(long);
                length -= 8*sizeof(long);
        }
        while (length >= 1) {
                temp ^= *(unsigned char *)zone;
                zone += 1;
                length--;
        }
        htotal = temp;
}

#define ALIGN_UP(x, align_to)   (((x) + ((align_to)-1)) & ~((align_to)-1))
#define ALIGN_PTR_UP(p, ptr_align_to)   ((typeof(p))ALIGN_UP((unsigned long)(p), ptr_align_to))


static void *mmap_large_buffer(size_t need, size_t *allocated)
{
        void *buffer;
        size_t sz;

        /* Attempt to use huge pages if possible. */
        sz = ALIGN_UP(need, map_align);
        buffer = mmap(NULL, sz, PROT_READ | PROT_WRITE,
                      MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);

        if (buffer == (void *)-1) {
                sz = need;
                buffer = mmap(NULL, sz, PROT_READ | PROT_WRITE,
                              MAP_PRIVATE | MAP_ANONYMOUS | MAP_POPULATE,
                              -1, 0);
                if (buffer != (void *)-1)
                        fprintf(stderr, "MAP_HUGETLB attempt failed, look at /sys/kernel/mm/hugepages for optimal performance\n");
        }
        *allocated = sz;
        return buffer;
}

static uint32_t tcp_info_get_rcv_mss(int fd)
{
        socklen_t sz = sizeof(struct tcp_info);
        struct tcp_info info;

        if (getsockopt(fd, IPPROTO_TCP, TCP_INFO, &info, &sz)) {
                fprintf(stderr, "Error fetching TCP_INFO\n");
                return 0;
        }

        return info.tcpi_rcv_mss;
}

void *child_thread(void *arg)
{
        unsigned char digest[SHA256_DIGEST_LENGTH];
        unsigned long total_mmap = 0, total = 0;
        struct tcp_zerocopy_receive zc;
        unsigned char *buffer = NULL;
        unsigned long delta_usec;
        EVP_MD_CTX *ctx = NULL;
        int flags = MAP_SHARED;
        struct timeval t0, t1;
        void *raddr = NULL;
        void *addr = NULL;
        double throughput;
        struct rusage ru;
        size_t buffer_sz;
        int lu, fd;

        fd = (int)(unsigned long)arg;

        gettimeofday(&t0, NULL);

        fcntl(fd, F_SETFL, O_NDELAY);
        buffer = mmap_large_buffer(chunk_size, &buffer_sz);
        if (buffer == (void *)-1) {
                perror("mmap");
                goto error;
        }
        if (zflg) {
                raddr = mmap(NULL, chunk_size + map_align, PROT_READ, flags, fd, 0);
                if (raddr == (void *)-1) {
                        perror("mmap");
                        zflg = 0;
                } else {
                        addr = ALIGN_PTR_UP(raddr, map_align);
                }
        }
        if (integrity) {
                ctx = EVP_MD_CTX_new();
                if (!ctx) {
                        perror("cannot enable SHA computing");
                        goto error;
                }
                EVP_DigestInit_ex(ctx, EVP_sha256(), NULL);
        }
        while (1) {
                struct pollfd pfd = { .fd = fd, .events = POLLIN, };
                int sub;

                poll(&pfd, 1, 10000);
                if (zflg) {
                        socklen_t zc_len = sizeof(zc);
                        int res;

                        memset(&zc, 0, sizeof(zc));
                        zc.address = (__u64)((unsigned long)addr);
                        zc.length = min(chunk_size, FILE_SZ - total);

                        res = getsockopt(fd, IPPROTO_TCP, TCP_ZEROCOPY_RECEIVE,
                                         &zc, &zc_len);
                        if (res == -1)
                                break;

                        if (zc.length) {
                                assert(zc.length <= chunk_size);
                                if (integrity)
                                        EVP_DigestUpdate(ctx, addr, zc.length);
                                total_mmap += zc.length;
                                if (xflg)
                                        hash_zone(addr, zc.length);
                                /* It is more efficient to unmap the pages right now,
                                 * instead of doing this in next TCP_ZEROCOPY_RECEIVE.
                                 */
                                madvise(addr, zc.length, MADV_DONTNEED);
                                total += zc.length;
                        }
                        if (zc.recv_skip_hint) {
                                assert(zc.recv_skip_hint <= chunk_size);
                                lu = read(fd, buffer, min(zc.recv_skip_hint,
                                                          FILE_SZ - total));
                                if (lu > 0) {
                                        if (integrity)
                                                EVP_DigestUpdate(ctx, buffer, lu);
                                        if (xflg)
                                                hash_zone(buffer, lu);
                                        total += lu;
                                }
                                if (lu == 0)
                                        goto end;
                        }
                        continue;
                }
                sub = 0;
                while (sub < chunk_size) {
                        lu = read(fd, buffer + sub, min(chunk_size - sub,
                                                        FILE_SZ - total));
                        if (lu == 0)
                                goto end;
                        if (lu < 0)
                                break;
                        if (integrity)
                                EVP_DigestUpdate(ctx, buffer + sub, lu);
                        if (xflg)
                                hash_zone(buffer + sub, lu);
                        total += lu;
                        sub += lu;
                }
        }
end:
        gettimeofday(&t1, NULL);
        delta_usec = (t1.tv_sec - t0.tv_sec) * 1000000 + t1.tv_usec - t0.tv_usec;

        if (integrity) {
                fcntl(fd, F_SETFL, 0);
                EVP_DigestFinal_ex(ctx, digest, &digest_len);
                lu = read(fd, buffer, SHA256_DIGEST_LENGTH);
                if (lu != SHA256_DIGEST_LENGTH)
                        perror("Error: Cannot read SHA256\n");

                if (memcmp(digest, buffer,
                           SHA256_DIGEST_LENGTH))
                        fprintf(stderr, "Error: SHA256 of the data is not right\n");
                else
                        printf("\nSHA256 is correct\n");
        }

        throughput = 0;
        if (delta_usec)
                throughput = total * 8.0 / (double)delta_usec / 1000.0;
        getrusage(RUSAGE_THREAD, &ru);
        if (total > 1024*1024) {
                unsigned long total_usec;
                unsigned long mb = total >> 20;
                total_usec = 1000000*ru.ru_utime.tv_sec + ru.ru_utime.tv_usec +
                             1000000*ru.ru_stime.tv_sec + ru.ru_stime.tv_usec;
                printf("received %lg MB (%lg %% mmap'ed) in %lg s, %lg Gbit\n"
                       "  cpu usage user:%lg sys:%lg, %lg usec per MB, %lu c-switches, rcv_mss %u\n",
                                total / (1024.0 * 1024.0),
                                100.0*total_mmap/total,
                                (double)delta_usec / 1000000.0,
                                throughput,
                                (double)ru.ru_utime.tv_sec + (double)ru.ru_utime.tv_usec / 1000000.0,
                                (double)ru.ru_stime.tv_sec + (double)ru.ru_stime.tv_usec / 1000000.0,
                                (double)total_usec/mb,
                                ru.ru_nvcsw,
                                tcp_info_get_rcv_mss(fd));
        }
error:
        munmap(buffer, buffer_sz);
        close(fd);
        if (zflg)
                munmap(raddr, chunk_size + map_align);
        pthread_exit(0);
}

static void apply_rcvsnd_buf(int fd)
{
        if (rcvbuf && setsockopt(fd, SOL_SOCKET,
                                 SO_RCVBUF, &rcvbuf, sizeof(rcvbuf)) == -1) {
                perror("setsockopt SO_RCVBUF");
        }

        if (sndbuf && setsockopt(fd, SOL_SOCKET,
                                 SO_SNDBUF, &sndbuf, sizeof(sndbuf)) == -1) {
                perror("setsockopt SO_SNDBUF");
        }
}


static void setup_sockaddr(int domain, const char *str_addr,
                           struct sockaddr_storage *sockaddr)
{
        struct sockaddr_in6 *addr6 = (void *) sockaddr;
        struct sockaddr_in *addr4 = (void *) sockaddr;

        switch (domain) {
        case PF_INET:
                memset(addr4, 0, sizeof(*addr4));
                addr4->sin_family = AF_INET;
                addr4->sin_port = htons(cfg_port);
                if (str_addr &&
                    inet_pton(AF_INET, str_addr, &(addr4->sin_addr)) != 1)
                        error(1, 0, "ipv4 parse error: %s", str_addr);
                break;
        case PF_INET6:
                memset(addr6, 0, sizeof(*addr6));
                addr6->sin6_family = AF_INET6;
                addr6->sin6_port = htons(cfg_port);
                if (str_addr &&
                    inet_pton(AF_INET6, str_addr, &(addr6->sin6_addr)) != 1)
                        error(1, 0, "ipv6 parse error: %s", str_addr);
                break;
        default:
                error(1, 0, "illegal domain");
        }
}

static void do_accept(int fdlisten)
{
        pthread_attr_t attr;
        int rcvlowat;

        pthread_attr_init(&attr);
        pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);

        rcvlowat = chunk_size;
        if (setsockopt(fdlisten, SOL_SOCKET, SO_RCVLOWAT,
                       &rcvlowat, sizeof(rcvlowat)) == -1) {
                perror("setsockopt SO_RCVLOWAT");
        }

        apply_rcvsnd_buf(fdlisten);

        while (1) {
                struct sockaddr_in addr;
                socklen_t addrlen = sizeof(addr);
                pthread_t th;
                int fd, res;

                fd = accept(fdlisten, (struct sockaddr *)&addr, &addrlen);
                if (fd == -1) {
                        perror("accept");
                        continue;
                }
                res = pthread_create(&th, &attr, child_thread,
                                     (void *)(unsigned long)fd);
                if (res) {
                        errno = res;
                        perror("pthread_create");
                        close(fd);
                }
        }
}

/* Each thread should reserve a big enough vma to avoid
 * spinlock collisions in ptl locks.
 * This size is 2MB on x86_64, and is exported in /proc/meminfo.
 */
static unsigned long default_huge_page_size(void)
{
        FILE *f = fopen("/proc/meminfo", "r");
        unsigned long hps = 0;
        size_t linelen = 0;
        char *line = NULL;

        if (!f)
                return 0;
        while (getline(&line, &linelen, f) > 0) {
                if (sscanf(line, "Hugepagesize:       %lu kB", &hps) == 1) {
                        hps <<= 10;
                        break;
                }
        }
        free(line);
        fclose(f);
        return hps;
}

static void randomize(void *target, size_t count)
{
        static int urandom = -1;
        ssize_t got;

        urandom = open("/dev/urandom", O_RDONLY);
        if (urandom < 0) {
                perror("open /dev/urandom");
                exit(1);
        }
        got = read(urandom, target, count);
        if (got != count) {
                perror("read /dev/urandom");
                exit(1);
        }
}

int main(int argc, char *argv[])
{
        unsigned char digest[SHA256_DIGEST_LENGTH];
        struct sockaddr_storage listenaddr, addr;
        unsigned int max_pacing_rate = 0;
        EVP_MD_CTX *ctx = NULL;
        unsigned char *buffer;
        uint64_t total = 0;
        char *host = NULL;
        int fd, c, on = 1;
        size_t buffer_sz;
        int sflg = 0;
        int mss = 0;

        while ((c = getopt(argc, argv, "46p:svr:w:H:zxkP:M:C:a:i")) != -1) {
                switch (c) {
                case '4':
                        cfg_family = PF_INET;
                        cfg_alen = sizeof(struct sockaddr_in);
                        break;
                case '6':
                        cfg_family = PF_INET6;
                        cfg_alen = sizeof(struct sockaddr_in6);
                        break;
                case 'p':
                        cfg_port = atoi(optarg);
                        break;
                case 'H':
                        host = optarg;
                        break;
                case 's': /* server : listen for incoming connections */
                        sflg++;
                        break;
                case 'r':
                        rcvbuf = atoi(optarg);
                        break;
                case 'w':
                        sndbuf = atoi(optarg);
                        break;
                case 'z':
                        zflg = 1;
                        break;
                case 'M':
                        mss = atoi(optarg);
                        break;
                case 'x':
                        xflg = 1;
                        break;
                case 'k':
                        keepflag = 1;
                        break;
                case 'P':
                        max_pacing_rate = atoi(optarg) ;
                        break;
                case 'C':
                        chunk_size = atol(optarg);
                        break;
                case 'a':
                        map_align = atol(optarg);
                        break;
                case 'i':
                        integrity = 1;
                        break;
                default:
                        exit(1);
                }
        }
        if (!map_align) {
                map_align = default_huge_page_size();
                /* if really /proc/meminfo is not helping,
                 * we use the default x86_64 hugepagesize.
                 */
                if (!map_align)
                        map_align = 2*1024*1024;
        }
        if (sflg) {
                int fdlisten = socket(cfg_family, SOCK_STREAM, 0);

                if (fdlisten == -1) {
                        perror("socket");
                        exit(1);
                }
                apply_rcvsnd_buf(fdlisten);
                setsockopt(fdlisten, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

                setup_sockaddr(cfg_family, host, &listenaddr);

                if (mss &&
                    setsockopt(fdlisten, IPPROTO_TCP, TCP_MAXSEG,
                               &mss, sizeof(mss)) == -1) {
                        perror("setsockopt TCP_MAXSEG");
                        exit(1);
                }
                if (bind(fdlisten, (const struct sockaddr *)&listenaddr, cfg_alen) == -1) {
                        perror("bind");
                        exit(1);
                }
                if (listen(fdlisten, 128) == -1) {
                        perror("listen");
                        exit(1);
                }
                do_accept(fdlisten);
        }

        buffer = mmap_large_buffer(chunk_size, &buffer_sz);
        if (buffer == (unsigned char *)-1) {
                perror("mmap");
                exit(1);
        }

        fd = socket(cfg_family, SOCK_STREAM, 0);
        if (fd == -1) {
                perror("socket");
                exit(1);
        }
        apply_rcvsnd_buf(fd);

        setup_sockaddr(cfg_family, host, &addr);

        if (mss &&
            setsockopt(fd, IPPROTO_TCP, TCP_MAXSEG, &mss, sizeof(mss)) == -1) {
                perror("setsockopt TCP_MAXSEG");
                exit(1);
        }
        if (connect(fd, (const struct sockaddr *)&addr, cfg_alen) == -1) {
                perror("connect");
                exit(1);
        }
        if (max_pacing_rate &&
            setsockopt(fd, SOL_SOCKET, SO_MAX_PACING_RATE,
                       &max_pacing_rate, sizeof(max_pacing_rate)) == -1)
                perror("setsockopt SO_MAX_PACING_RATE");

        if (zflg && setsockopt(fd, SOL_SOCKET, SO_ZEROCOPY,
                               &on, sizeof(on)) == -1) {
                perror("setsockopt SO_ZEROCOPY, (-z option disabled)");
                zflg = 0;
        }
        if (integrity) {
                randomize(buffer, buffer_sz);
                ctx = EVP_MD_CTX_new();
                if (!ctx) {
                        perror("cannot enable SHA computing");
                        exit(1);
                }
                EVP_DigestInit_ex(ctx, EVP_sha256(), NULL);
        }
        while (total < FILE_SZ) {
                size_t offset = total % chunk_size;
                int64_t wr = FILE_SZ - total;

                if (wr > chunk_size - offset)
                        wr = chunk_size - offset;
                /* Note : we just want to fill the pipe with random bytes */
                wr = send(fd, buffer + offset,
                          (size_t)wr, zflg ? MSG_ZEROCOPY : 0);
                if (wr <= 0)
                        break;
                if (integrity)
                        EVP_DigestUpdate(ctx, buffer + offset, wr);
                total += wr;
        }
        if (integrity && total == FILE_SZ) {
                EVP_DigestFinal_ex(ctx, digest, &digest_len);
                send(fd, digest, (size_t)SHA256_DIGEST_LENGTH, 0);
        }
        close(fd);
        munmap(buffer, buffer_sz);
        return 0;
}