From 4d33c00e04afebd9a223d151cb7545ac87d7eeb1 Mon Sep 17 00:00:00 2001 From: "Nicholas J. Kain" Date: Tue, 20 Oct 2020 05:54:00 -0400 Subject: [PATCH] Use poll() instead of epoll() for ndhc-master. --- src/arp.c | 4 +- src/dhcp.c | 2 - src/ndhc.c | 160 ++++++++++++++++++++++++++++++----------------------- src/ndhc.h | 2 +- src/sys.c | 29 +--------- src/sys.h | 6 +- 6 files changed, 96 insertions(+), 107 deletions(-) diff --git a/src/arp.c b/src/arp.c index b7bddd0..d04109b 100644 --- a/src/arp.c +++ b/src/arp.c @@ -83,7 +83,6 @@ static void arp_min_close_fd(struct client_state_t cs[static 1]) { if (cs->arpFd < 0) return; - epoll_del(cs->epollFd, cs->arpFd); close(cs->arpFd); cs->arpFd = -1; cs->arp_is_defense = false; @@ -161,7 +160,6 @@ static int arp_open_fd(struct client_state_t cs[static 1], bool defense) client_config.interface, __func__, strerror(errno)); return -1; } - epoll_add(cs->epollFd, cs->arpFd); return 0; } @@ -754,6 +752,8 @@ server_is_router: bool arp_packet_get(struct client_state_t cs[static 1]) { + if (cs->arpFd < 0) + return false; struct arpMsg amsg; ssize_t r = 0; size_t bytes_read = 0; diff --git a/src/dhcp.c b/src/dhcp.c index 162f001..c5e824c 100644 --- a/src/dhcp.c +++ b/src/dhcp.c @@ -327,14 +327,12 @@ void start_dhcp_listen(struct client_state_t cs[static 1]) if (cs->listenFd < 0) suicide("%s: FATAL: Couldn't listen on socket: %s", client_config.interface, strerror(errno)); - epoll_add(cs->epollFd, cs->listenFd); } void stop_dhcp_listen(struct client_state_t cs[static 1]) { if (cs->listenFd < 0) return; - epoll_del(cs->epollFd, cs->listenFd); close(cs->listenFd); cs->listenFd = -1; } diff --git a/src/ndhc.c b/src/ndhc.c index 09a63ef..98ed092 100644 --- a/src/ndhc.c +++ b/src/ndhc.c @@ -40,7 +40,7 @@ #include #include #include -#include +#include #include #include #include @@ -73,7 +73,6 @@ struct client_state_t cs = { .program_init = true, - .epollFd = -1, .listenFd = -1, .arpFd = -1, .nlFd = -1, @@ -279,33 +278,35 @@ static void do_ndhc_work(void) static bool rfkill_set; // Is the rfkill switch set? static bool rfkill_nl_carrier_wentup; // iface carrier changed to up during rfkill struct dhcpmsg dhcp_packet; - struct epoll_event events[1]; long long nowts; int timeout = 0; bool had_event; - cs.epollFd = epoll_create1(0); - if (cs.epollFd < 0) - suicide("epoll_create1 failed"); - setup_signals_ndhc(); - - epoll_add(cs.epollFd, cs.nlFd); - epoll_add(cs.epollFd, ifchStream[0]); - epoll_add(cs.epollFd, sockdStream[0]); - if (client_config.enable_rfkill && cs.rfkillFd != -1) - epoll_add(cs.epollFd, cs.rfkillFd); start_dhcp_listen(&cs); + struct pollfd pfds[6] = {0}; + pfds[0].fd = cs.nlFd; + pfds[0].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP; + pfds[1].fd = ifchStream[0]; + pfds[1].events = POLLHUP|POLLERR|POLLRDHUP; + pfds[2].fd = sockdStream[0]; + pfds[2].events = POLLHUP|POLLERR|POLLRDHUP; + pfds[3].fd = cs.rfkillFd; + pfds[3].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP; + // These can change on the fly. + pfds[4].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP; + pfds[5].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP; + for (;;) { + pfds[4].fd = cs.arpFd; + pfds[5].fd = cs.listenFd; had_event = false; - int maxi = epoll_wait(cs.epollFd, events, 1, timeout); - if (maxi < 0) { - if (errno == EINTR) - continue; - else - suicide("epoll_wait failed"); + if (poll(pfds, 6, timeout) < 0) { + if (errno == EINTR) continue; + else suicide("poll failed"); } + bool sev_dhcp = false; uint32_t dhcp_srcaddr; uint8_t dhcp_msgtype; @@ -313,34 +314,54 @@ static void do_ndhc_work(void) int sev_nl = IFS_NONE; int sev_rfk = RFK_NONE; bool force_fingerprint = false; - for (int i = 0; i < maxi; ++i) { + if (pfds[0].revents & POLLIN) { + pfds[0].revents &= ~POLLIN; had_event = true; - int fd = events[i].data.fd; - if (fd == cs.listenFd) { - if (!(events[i].events & EPOLLIN)) - suicide("listenfd closed unexpectedly"); + sev_nl = nl_event_get(&cs); + } + if (pfds[0].revents & (POLLHUP|POLLERR|POLLRDHUP)) { + pfds[0].revents &= ~(POLLHUP|POLLERR|POLLRDHUP); + suicide("nlfd closed unexpectedly"); + } + if (pfds[1].revents & (POLLHUP|POLLERR|POLLRDHUP)) { + pfds[1].revents &= ~(POLLHUP|POLLERR|POLLRDHUP); + exit(EXIT_FAILURE); + } + if (pfds[2].revents & (POLLHUP|POLLERR|POLLRDHUP)) { + pfds[2].revents &= ~(POLLHUP|POLLERR|POLLRDHUP); + exit(EXIT_FAILURE); + } + if (pfds[3].revents & POLLIN) { + pfds[3].revents &= ~POLLIN; + had_event = true; + sev_rfk = rfkill_get(&cs, 1, client_config.rfkillIdx); + } + if (pfds[3].revents & (POLLHUP|POLLERR|POLLRDHUP)) { + pfds[3].revents &= ~(POLLHUP|POLLERR|POLLRDHUP); + suicide("rfkillfd closed unexpectedly"); + } + if (pfds[4].revents & POLLIN) { + pfds[4].revents &= ~POLLIN; + had_event = true; + // Make sure the fd is still the same. + if (pfds[4].fd == cs.arpFd) + sev_arp = arp_packet_get(&cs); + } + if (pfds[4].revents & (POLLHUP|POLLERR|POLLRDHUP)) { + pfds[4].revents &= ~(POLLHUP|POLLERR|POLLRDHUP); + suicide("arpfd closed unexpectedly"); + } + if (pfds[5].revents & POLLIN) { + pfds[5].revents &= ~POLLIN; + had_event = true; + // Make sure the fd is still the same. + if (pfds[5].fd == cs.listenFd) sev_dhcp = dhcp_packet_get(&cs, &dhcp_packet, &dhcp_msgtype, &dhcp_srcaddr); - } else if (fd == cs.arpFd) { - if (!(events[i].events & EPOLLIN)) - suicide("arpfd closed unexpectedly"); - sev_arp = arp_packet_get(&cs); - } else if (fd == cs.nlFd) { - if (!(events[i].events & EPOLLIN)) - suicide("nlfd closed unexpectedly"); - sev_nl = nl_event_get(&cs); - } else if (fd == ifchStream[0]) { - if (events[i].events & (EPOLLHUP|EPOLLERR|EPOLLRDHUP)) - exit(EXIT_FAILURE); - } else if (fd == sockdStream[0]) { - if (events[i].events & (EPOLLHUP|EPOLLERR|EPOLLRDHUP)) - exit(EXIT_FAILURE); - } else if (fd == cs.rfkillFd && client_config.enable_rfkill) { - if (!(events[i].events & EPOLLIN)) - suicide("rfkillfd closed unexpectedly"); - sev_rfk = rfkill_get(&cs, 1, client_config.rfkillIdx); - } else - suicide("epoll_wait: unknown fd"); + } + if (pfds[5].revents & (POLLHUP|POLLERR|POLLRDHUP)) { + pfds[5].revents &= ~(POLLHUP|POLLERR|POLLRDHUP); + suicide("listenfd closed unexpectedly"); } if (sev_rfk == RFK_ENABLED) { @@ -371,6 +392,10 @@ static void do_ndhc_work(void) continue; } + // These two can change on the fly; make sure the event is current. + if (pfds[4].fd != cs.arpFd) sev_arp = false; + if (pfds[5].fd != cs.listenFd) sev_dhcp = false; + nowts = curms(); long long arp_wake_ts = arp_get_wake_ts(); int dhcp_ok = dhcp_handle(&cs, nowts, sev_dhcp, &dhcp_packet, @@ -514,42 +539,37 @@ void background(void) static void wait_for_rfkill() { - struct epoll_event events[2]; cs.rfkillFd = rfkill_open(&client_config.enable_rfkill); if (cs.rfkillFd < 0) suicide("can't wait for rfkill to end if /dev/rfkill can't be opened"); - int epfd = epoll_create1(0); - if (epfd < 0) - suicide("epoll_create1 failed"); - epoll_add(epfd, cs.rfkillFd); + + struct pollfd pfds[1] = {0}; + pfds[0].events = POLLIN|POLLHUP|POLLERR|POLLRDHUP; for (;;) { - int r = epoll_wait(epfd, events, 2, -1); - if (r < 0) { - if (errno == EINTR) - continue; - else - suicide("epoll_wait failed"); + pfds[0].fd = cs.rfkillFd; + if (poll(pfds, 1, -1) < 0) { + if (errno == EINTR) continue; + else suicide("poll failed"); } - for (int i = 0; i < r; ++i) { - int fd = events[i].data.fd; - if (fd != cs.rfkillFd) - suicide("epoll_wait: unknown fd"); - if (events[i].events & EPOLLIN) { - int rfk = rfkill_get(&cs, 0, 0); - if (rfk == RFK_DISABLED) { - switch (perform_ifup()) { - case 1: case 0: goto rfkill_gone; - case -3: - log_line("rfkill: radio immediately blocked again; spurious?"); - break; - default: suicide("failed to set the interface to up state"); - } + if (pfds[0].revents & POLLIN) { + pfds[0].revents &= ~POLLIN; + if (rfkill_get(&cs, 0, 0) == RFK_DISABLED) { + switch (perform_ifup()) { + case 1: + case 0: goto rfkill_gone; + case -3: + log_line("rfkill: radio immediately blocked again; spurious?"); + break; + default: suicide("failed to set the interface to up state"); } } } + if (pfds[0].revents & (POLLHUP|POLLERR|POLLRDHUP)) { + pfds[0].revents &= ~(POLLHUP|POLLERR|POLLRDHUP); + suicide("rfkillFd closed unexpectedly"); + } } rfkill_gone: - close(epfd); // We always close because ifchd and sockd shouldn't keep // an rfkill fd open. close(cs.rfkillFd); diff --git a/src/ndhc.h b/src/ndhc.h index 9d0b0a7..d01842b 100644 --- a/src/ndhc.h +++ b/src/ndhc.h @@ -45,7 +45,7 @@ struct client_state_t { long long leaseStartTime, renewTime, rebindTime; long long dhcp_wake_ts; int ifDeconfig; // Set if the interface has already been deconfigured. - int epollFd, listenFd, arpFd, nlFd, rfkillFd; + int listenFd, arpFd, nlFd, rfkillFd; int server_arp_sent, router_arp_sent; uint32_t nlPortId; unsigned int num_dhcp_requests, num_dhcp_renews; diff --git a/src/sys.c b/src/sys.c index 35dcefd..f4e5b21 100644 --- a/src/sys.c +++ b/src/sys.c @@ -1,4 +1,4 @@ -/* sys.c - linux-specific signal and epoll functions +/* sys.c - misc portable functions * * Copyright 2010-2020 Nicholas J. Kain * All rights reserved. @@ -26,14 +26,11 @@ * POSSIBILITY OF SUCH DAMAGE. */ -#include -#include #include #include #include -#include +#include #include "nk/log.h" -#include "nk/io.h" #include "ndhc.h" #include "sys.h" @@ -47,28 +44,6 @@ long long IMPL_curms(const char *parent_function) return ts.tv_sec * 1000LL + ts.tv_nsec / 1000000LL; } -void epoll_add(int epfd, int fd) -{ - struct epoll_event ev; - int r; - ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP; - ev.data.fd = fd; - r = epoll_ctl(epfd, EPOLL_CTL_ADD, fd, &ev); - if (r < 0) - suicide("epoll_add failed %s", strerror(errno)); -} - -void epoll_del(int epfd, int fd) -{ - struct epoll_event ev; - int r; - ev.events = EPOLLIN | EPOLLRDHUP | EPOLLERR | EPOLLHUP; - ev.data.fd = fd; - r = epoll_ctl(epfd, EPOLL_CTL_DEL, fd, &ev); - if (r < 0) - suicide("epoll_del failed %s", strerror(errno)); -} - void setup_signals_subprocess(void) { sigset_t mask; diff --git a/src/sys.h b/src/sys.h index c76d317..3194af1 100644 --- a/src/sys.h +++ b/src/sys.h @@ -1,4 +1,4 @@ -/* sys.h - linux-specific signal and epoll functions +/* sys.h - misc portable functions * * Copyright 2010-2020 Nicholas J. Kain * All rights reserved. @@ -28,7 +28,6 @@ #ifndef SYS_H_ #define SYS_H_ -#include #include "ndhc-defines.h" static inline size_t min_size_t(size_t a, size_t b) @@ -38,11 +37,8 @@ static inline size_t min_size_t(size_t a, size_t b) #define curms() IMPL_curms(__func__) long long IMPL_curms(const char *parent_function); -void epoll_add(int epfd, int fd); -void epoll_del(int epfd, int fd); void setup_signals_subprocess(void); -void signal_dispatch_subprocess(int sfd, const char pname[static 1]); #endif /* SYS_H_ */