From: Paul Mackerras Date: Fri, 5 Aug 2022 04:10:40 +0000 (+1000) Subject: Merge pull request #354 from pali/register-with-name X-Git-Tag: ppp-2.5.0~33 X-Git-Url: https://git.ozlabs.org/?p=ppp.git;a=commitdiff_plain;h=607d8eadccfd62c1fa84a36bd1440bd48b4e55ca;hp=-c Merge pull request #354 from pali/register-with-name pppd: Add support for registering ppp interface via Linux rtnetlink API --- 607d8eadccfd62c1fa84a36bd1440bd48b4e55ca diff --combined pppd/sys-linux.c index ff3a249,6eed86f..e7f851c --- a/pppd/sys-linux.c +++ b/pppd/sys-linux.c @@@ -81,7 -81,6 +81,7 @@@ #include #include #include +#include #include #include @@@ -126,11 -125,17 +126,12 @@@ #include #include -#include -#include +#include #include #include #include + -#ifdef INET6 -#include -#endif - /* Attempt at retaining compile-support with older than 4.7 kernels, or kernels * where RTM_NEWSTATS isn't defined for whatever reason. */ @@@ -138,8 -143,8 +139,10 @@@ #define RTM_NEWSTATS 92 #define RTM_GETSTATS 94 #define IFLA_STATS_LINK_64 1 + #endif +#include ++ /* glibc versions prior to 2.24 do not define SOL_NETLINK */ #ifndef SOL_NETLINK #define SOL_NETLINK 270 @@@ -149,20 -154,21 +152,25 @@@ #ifndef NETLINK_CAP_ACK #define NETLINK_CAP_ACK 10 #endif + + /* linux kernel versions prior to 4.7 do not define/support IFLA_PPP_DEV_FD */ + #ifndef IFLA_PPP_MAX + /* IFLA_PPP_DEV_FD is declared as enum when IFLA_PPP_MAX is defined */ + #define IFLA_PPP_DEV_FD 1 #endif #include "pppd.h" #include "fsm.h" #include "ipcp.h" -#ifdef PPP_FILTER +#ifdef PPP_WITH_IPV6CP +#include "eui64.h" +#endif /* PPP_WITH_IPV6CP */ + +#ifdef PPP_WITH_FILTER #include #include -#endif /* PPP_FILTER */ +#endif /* PPP_WITH_FILTER */ #ifdef LOCKLIB #include @@@ -174,7 -180,7 +182,7 @@@ */ #include "termios_linux.h" -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP #ifndef _LINUX_IN6_H /* * This is in linux/include/net/ipv6.h. @@@ -194,7 -200,7 +202,7 @@@ struct in6_ifreq } while (0) static const eui64_t nulleui64; -#endif /* INET6 */ +#endif /* PPP_WITH_IPV6CP */ /* We can get an EIO error on an ioctl if the modem has hung up */ #define ok_error(num) ((num)==EIO) @@@ -206,9 -212,9 +214,9 @@@ static int ppp_fd = -1; /* fd which i static int sock_fd = -1; /* socket for doing interface ioctls */ static int slave_fd = -1; /* pty for old-style demand mode, slave */ static int master_fd = -1; /* pty for old-style demand mode, master */ -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP static int sock6_fd = -1; -#endif /* INET6 */ +#endif /* PPP_WITH_IPV6CP */ /* * For the old-style kernel driver, this is the same as ppp_fd. @@@ -351,7 -357,7 +359,7 @@@ void sys_init(void if (sock_fd < 0) fatal("Couldn't create IP socket: %m(%d)", errno); -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP sock6_fd = socket(AF_INET6, SOCK_DGRAM, 0); if (sock6_fd < 0) sock6_fd = -errno; /* save errno for later */ @@@ -377,17 -383,15 +385,17 @@@ void sys_cleanup(void if_is_up = 0; sifdown(0); } +#ifdef PPP_WITH_IPV6CP if (if6_is_up) sif6down(0); +#endif /* * Delete any routes through the device. */ if (have_default_route) cifdefaultroute(0, 0, 0); -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP if (have_default_route6) cif6defaultroute(0, nulleui64, nulleui64); #endif @@@ -407,7 -411,7 +415,7 @@@ sys_close(void close(ppp_dev_fd); if (sock_fd >= 0) close(sock_fd); -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP if (sock6_fd >= 0) close(sock6_fd); #endif @@@ -662,6 -666,160 +670,160 @@@ void generic_disestablish_ppp(int dev_f } } + /* + * make_ppp_unit_rtnetlink - register a new ppp network interface for ppp_dev_fd + * with specified req_ifname via rtnetlink. Interface name req_ifname must not + * be empty. Custom ppp unit id req_unit is ignored and kernel choose some free. + */ + static int make_ppp_unit_rtnetlink(void) + { + struct { + struct nlmsghdr nlh; + struct ifinfomsg ifm; + struct { + struct rtattr rta; + char ifname[IFNAMSIZ]; + } ifn; + struct { + struct rtattr rta; + struct { + struct rtattr rta; + char ifkind[sizeof("ppp")]; + } ifik; + struct { + struct rtattr rta; + struct { + struct rtattr rta; + union { + int ppp_dev_fd; + } ppp; + } ifdata[1]; + } ifid; + } ifli; + } nlreq; + struct { + struct nlmsghdr nlh; + struct nlmsgerr nlerr; + } nlresp; + struct sockaddr_nl nladdr; + struct iovec iov; + struct msghdr msg; + ssize_t nlresplen; + int one; + int fd; + + fd = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE); + if (fd < 0) { + error("make_ppp_unit_rtnetlink: socket(NETLINK_ROUTE): %m (line %d)", __LINE__); + return 0; + } + + /* Tell kernel to not send to us payload of acknowledgment error message. */ + one = 1; + setsockopt(fd, SOL_NETLINK, NETLINK_CAP_ACK, &one, sizeof(one)); + + memset(&nladdr, 0, sizeof(nladdr)); + nladdr.nl_family = AF_NETLINK; + + if (bind(fd, (struct sockaddr *)&nladdr, sizeof(nladdr)) < 0) { + error("make_ppp_unit_rtnetlink: bind(AF_NETLINK): %m (line %d)", __LINE__); + close(fd); + return 0; + } + + memset(&nlreq, 0, sizeof(nlreq)); + nlreq.nlh.nlmsg_len = sizeof(nlreq); + nlreq.nlh.nlmsg_type = RTM_NEWLINK; + nlreq.nlh.nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | NLM_F_EXCL | NLM_F_CREATE; + nlreq.ifm.ifi_family = AF_UNSPEC; + nlreq.ifm.ifi_type = ARPHRD_NETROM; + nlreq.ifn.rta.rta_len = sizeof(nlreq.ifn); + nlreq.ifn.rta.rta_type = IFLA_IFNAME; + strlcpy(nlreq.ifn.ifname, req_ifname, sizeof(nlreq.ifn.ifname)); + nlreq.ifli.rta.rta_len = sizeof(nlreq.ifli); + nlreq.ifli.rta.rta_type = IFLA_LINKINFO; + nlreq.ifli.ifik.rta.rta_len = sizeof(nlreq.ifli.ifik); + nlreq.ifli.ifik.rta.rta_type = IFLA_INFO_KIND; + strcpy(nlreq.ifli.ifik.ifkind, "ppp"); + nlreq.ifli.ifid.rta.rta_len = sizeof(nlreq.ifli.ifid); + nlreq.ifli.ifid.rta.rta_type = IFLA_INFO_DATA; + nlreq.ifli.ifid.ifdata[0].rta.rta_len = sizeof(nlreq.ifli.ifid.ifdata[0]); + nlreq.ifli.ifid.ifdata[0].rta.rta_type = IFLA_PPP_DEV_FD; + nlreq.ifli.ifid.ifdata[0].ppp.ppp_dev_fd = ppp_dev_fd; + + memset(&nladdr, 0, sizeof(nladdr)); + nladdr.nl_family = AF_NETLINK; + + memset(&iov, 0, sizeof(iov)); + iov.iov_base = &nlreq; + iov.iov_len = sizeof(nlreq); + + memset(&msg, 0, sizeof(msg)); + msg.msg_name = &nladdr; + msg.msg_namelen = sizeof(nladdr); + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + + if (sendmsg(fd, &msg, 0) < 0) { + error("make_ppp_unit_rtnetlink: sendmsg(RTM_NEWLINK/NLM_F_CREATE): %m (line %d)", __LINE__); + close(fd); + return 0; + } + + memset(&iov, 0, sizeof(iov)); + iov.iov_base = &nlresp; + iov.iov_len = sizeof(nlresp); + + memset(&msg, 0, sizeof(msg)); + msg.msg_name = &nladdr; + msg.msg_namelen = sizeof(nladdr); + msg.msg_iov = &iov; + msg.msg_iovlen = 1; + + nlresplen = recvmsg(fd, &msg, 0); + + if (nlresplen < 0) { + error("make_ppp_unit_rtnetlink: recvmsg(NLM_F_ACK): %m (line %d)", __LINE__); + close(fd); + return 0; + } + + close(fd); + + if (nladdr.nl_family != AF_NETLINK) { + error("make_ppp_unit_rtnetlink: recvmsg(NLM_F_ACK): Not a netlink packet (line %d)", __LINE__); + return 0; + } + + if ((size_t)nlresplen < sizeof(nlresp) || nlresp.nlh.nlmsg_len < sizeof(nlresp)) { + error("make_ppp_unit_rtnetlink: recvmsg(NLM_F_ACK): Acknowledgment netlink packet too short (line %d)", __LINE__); + return 0; + } + + /* acknowledgment packet for NLM_F_ACK is NLMSG_ERROR */ + if (nlresp.nlh.nlmsg_type != NLMSG_ERROR) { + error("make_ppp_unit_rtnetlink: recvmsg(NLM_F_ACK): Not an acknowledgment netlink packet (line %d)", __LINE__); + return 0; + } + + /* error == 0 indicates success, negative value is errno code */ + if (nlresp.nlerr.error != 0) { + /* + * Linux kernel versions prior to 4.7 do not support creating ppp + * interfaces via rtnetlink API and therefore error response is + * expected. On older kernel versions do not show this error message. + * When error is different than EEXIST then pppd tries to fallback to + * the old ioctl method. + */ + errno = (nlresp.nlerr.error < 0) ? -nlresp.nlerr.error : EINVAL; + if (kernel_version >= KVERSION(4,7,0)) + error("Couldn't create ppp interface %s: %m", req_ifname); + return 0; + } + + return 1; + } + /* * make_ppp_unit - make a new ppp unit for ppp_dev_fd. * Assumes new_style_driver. @@@ -682,6 -840,33 +844,33 @@@ static int make_ppp_unit(void || fcntl(ppp_dev_fd, F_SETFL, flags | O_NONBLOCK) == -1) warn("Couldn't set /dev/ppp to nonblock: %m"); + /* + * Via rtnetlink it is possible to create ppp network interface with + * custom ifname atomically. But it is not possible to specify custom + * ppp unit id. + * + * Tools like systemd, udev or NetworkManager are trying to query + * interface attributes based on interface name immediately when new + * network interface is created. And therefore immediate interface + * renaming is causing issues. + * + * So use rtnetlink API only when user requested custom ifname. It will + * avoid system issues with interface renaming. + */ + if (req_unit == -1 && req_ifname[0] != '\0' && kernel_version >= KVERSION(2,1,16)) { + if (make_ppp_unit_rtnetlink()) { + if (ioctl(ppp_dev_fd, PPPIOCGUNIT, &ifunit)) + fatal("Couldn't retrieve PPP unit id: %m"); + return 0; + } + /* + * If interface with requested name already exist return error + * otherwise fallback to old ioctl method. + */ + if (errno == EEXIST) + return -1; + } + ifunit = req_unit; x = ioctl(ppp_dev_fd, PPPIOCNEWUNIT, &ifunit); if (x < 0 && req_unit >= 0 && errno == EEXIST) { @@@ -1427,7 -1612,7 +1616,7 @@@ void ccp_flags_set (int unit, int isope modify_flags(ppp_dev_fd, SC_CCP_OPEN|SC_CCP_UP, x); } -#ifdef PPP_FILTER +#ifdef PPP_WITH_FILTER /* * set_filters - set the active and pass filters in the kernel driver. */ @@@ -1452,7 -1637,7 +1641,7 @@@ int set_filters(struct bpf_program *pas } return 1; } -#endif /* PPP_FILTER */ +#endif /* PPP_WITH_FILTER */ /******************************************************************** * @@@ -1477,21 -1662,20 +1666,21 @@@ get_ppp_stats_ioctl(int u, struct pppd_ static u_int32_t iwraps = 0; static u_int32_t owraps = 0; - struct ifpppstatsreq req; + struct ifreq req; + struct ppp_stats data; memset (&req, 0, sizeof (req)); - req.stats_ptr = (caddr_t) &req.stats; - strlcpy(req.ifr__name, ifname, sizeof(req.ifr__name)); + req.ifr_data = (caddr_t) &data; + strlcpy(req.ifr_name, ifname, sizeof(req.ifr_name)); if (ioctl(sock_fd, SIOCGPPPSTATS, &req) < 0) { error("Couldn't get PPP statistics: %m"); return 0; } - stats->bytes_in = req.stats.p.ppp_ibytes; - stats->bytes_out = req.stats.p.ppp_obytes; - stats->pkts_in = req.stats.p.ppp_ipackets; - stats->pkts_out = req.stats.p.ppp_opackets; + stats->bytes_in = data.p.ppp_ibytes; + stats->bytes_out = data.p.ppp_obytes; + stats->pkts_in = data.p.ppp_ipackets; + stats->pkts_out = data.p.ppp_opackets; if (stats->bytes_in < previbytes) ++iwraps; @@@ -2109,7 -2293,7 +2298,7 @@@ int cifdefaultroute (int unit, u_int32_ return 1; } -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP /* * /proc/net/ipv6_route parsing stuff. */ @@@ -2299,7 -2483,7 +2488,7 @@@ int cif6defaultroute (int unit, eui64_ return 1; } -#endif /* INET6 */ +#endif /* PPP_WITH_IPV6CP */ /******************************************************************** * @@@ -2925,15 -3109,15 +3114,15 @@@ int sifdown (int u if (if_is_up && --if_is_up > 0) return 1; -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP if (if6_is_up) return 1; -#endif /* INET6 */ +#endif /* PPP_WITH_IPV6CP */ return setifstate(u, 0); } -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP /******************************************************************** * * sif6up - Config the interface up for IPv6 @@@ -2964,7 -3148,7 +3153,7 @@@ int sif6down (int u return setifstate(u, 0); } -#endif /* INET6 */ +#endif /* PPP_WITH_IPV6CP */ /******************************************************************** * @@@ -3152,7 -3336,7 +3341,7 @@@ int cifaddr (int unit, u_int32_t our_ad return 1; } -#ifdef INET6 +#ifdef PPP_WITH_IPV6CP /******************************************************************** * * sif6addr_rtnetlink - Config the interface with both IPv6 link-local addresses via rtnetlink @@@ -3413,7 -3597,7 +3602,7 @@@ int cif6addr (int unit, eui64_t our_eui } return 1; } -#endif /* INET6 */ +#endif /* PPP_WITH_IPV6CP */ /* * get_pty - get a pty master/slave pair and chown the slave side