110 lines
2.4 KiB
C++
110 lines
2.4 KiB
C++
#include <fcntl.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include "disk_backend_nbd.h"
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#include "log.h"
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#ifdef ESP32
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#include <lwip/netdb.h>
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#include <lwip/sockets.h>
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#else
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#include <netdb.h>
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#include <sys/socket.h>
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#endif
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disk_backend_nbd::disk_backend_nbd(const std::string & host, const int port) :
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host(host),
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port(port)
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{
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}
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disk_backend_nbd::~disk_backend_nbd()
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{
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close(fd);
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}
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bool disk_backend_nbd::begin()
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{
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if (!connect(false)) {
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DOLOG(ll_error, true, "disk_backend_nbd: cannot connect to NBD server");
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return false;
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}
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DOLOG(info, true, "disk_backend_nbd: connected to NBD server");
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return true;
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}
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bool disk_backend_nbd::connect(const bool retry)
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{
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do {
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// LOOP until connected, logging message, exponential backoff?
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addrinfo *res = nullptr;
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addrinfo hints { 0 };
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hints.ai_family = AF_INET;
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hints.ai_socktype = SOCK_STREAM;
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char port_str[8] { 0 };
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snprintf(port_str, sizeof port_str, "%d", port);
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int rc = getaddrinfo(host.c_str(), port_str, &hints, &res);
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if (rc != 0) {
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#ifdef ESP32
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DOLOG(ll_error, true, "disk_backend_nbd: cannot resolve \"%s\":%s", host.c_str(), port_str);
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#else
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DOLOG(ll_error, true, "disk_backend_nbd: cannot resolve \"%s\":%s: %s", host.c_str(), port_str, gai_strerror(rc));
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#endif
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sleep(1);
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continue;
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}
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for(addrinfo *p = res; p != NULL; p = p->ai_next) {
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if ((fd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) {
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continue;
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}
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if (::connect(fd, p->ai_addr, p->ai_addrlen) == -1) {
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close(fd);
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fd = -1;
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DOLOG(ll_error, true, "disk_backend_nbd: cannot connect");
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continue;
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}
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break;
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}
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freeaddrinfo(res);
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}
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while(fd == -1 && retry);
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return fd != -1;
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}
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bool disk_backend_nbd::read(const off_t offset, const size_t n, uint8_t *const target)
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{
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DOLOG(debug, false, "disk_backend_nbd::read: read %zu bytes from offset %zu", n, offset);
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connect(true);
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// TODO: loop dat als read() aangeeft dat de peer weg is, dat er dan gereconnect wordt
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// anders return false
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return pread(fd, target, n, offset) == ssize_t(n);
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}
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bool disk_backend_nbd::write(const off_t offset, const size_t n, const uint8_t *const from)
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{
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DOLOG(debug, false, "disk_backend_nbd::write: write %zu bytes to offset %zu", n, offset);
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connect(true);
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// TODO: loop dat als write() aangeeft dat de peer weg is, dat er dan gereconnect wordt
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// anders return false
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return pwrite(fd, from, n, offset) == ssize_t(n);
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}
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