From e59eb52fadb8b286e4ec15202be08a7024c434a2 Mon Sep 17 00:00:00 2001 From: Dan Smith Date: Thu, 26 Jun 2008 16:07:48 +0000 Subject: [PATCH] [LXC] Add functions to manage veth device pairs This gives us the ability to create a veth pair so that we can move one into the network namespace of an LXC container. --- src/Makefile.am | 1 + src/veth.c | 219 ++++++++++++++++++++++++++++++++++++++++++++++++ src/veth.h | 24 ++++++ 3 files changed, 244 insertions(+) create mode 100644 src/veth.c create mode 100644 src/veth.h diff --git a/src/Makefile.am b/src/Makefile.am index a5e4d3b620..a0957e2ef2 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -64,6 +64,7 @@ CLIENT_SOURCES = \ lxc_driver.c lxc_driver.h \ lxc_conf.c lxc_conf.h \ lxc_container.c lxc_container.h \ + veth.c veth.h \ nodeinfo.h nodeinfo.c \ util.c util.h diff --git a/src/veth.c b/src/veth.c new file mode 100644 index 0000000000..949496357c --- /dev/null +++ b/src/veth.c @@ -0,0 +1,219 @@ +/* + * veth.c: Tools for managing veth pairs + * + * Copyright IBM Corp. 2008 + * + * See COPYING.LIB for the License of this software + * + * Authors: + * David L. Leskovec + */ + +#include + +#include + +#include "veth.h" +#include "internal.h" +#include "memory.h" +#include "util.h" + +#define DEBUG(fmt,...) VIR_DEBUG(__FILE__, fmt, __VA_ARGS__) +#define DEBUG0(msg) VIR_DEBUG(__FILE__, "%s", msg) + +/* Functions */ +/** + * getFreeVethName: + * @veth: name for veth device (NULL to find first open) + * @maxLen: max length of veth name + * @startDev: device number to start at (x in vethx) + * + * Looks in /sys/class/net/ to find the first available veth device + * name. + * + * Returns 0 on success or -1 in case of error + */ +static int getFreeVethName(char *veth, int maxLen, int startDev) +{ + int rc = -1; + int devNum = startDev; + char path[PATH_MAX]; + + do { + snprintf(path, PATH_MAX, "/sys/class/net/veth%d/", devNum); + ++devNum; + } while (virFileExists(path)); + + snprintf(veth, maxLen, "veth%d", devNum); + + rc = devNum; + + return rc; +} + +/** + * vethCreate: + * @veth1: name for one end of veth pair + * @veth1MaxLen: max length of veth1 name + * @veth2: name for one end of veth pair + * @veth2MaxLen: max length of veth1 name + * + * Creates a veth device pair using the ip command: + * ip link add veth1 type veth peer name veth2 + * NOTE: If veth1 and veth2 names are not specified, ip will auto assign + * names. There seems to be two problems here - + * 1) There doesn't seem to be a way to determine the names of the + * devices that it creates. They show up in ip link show and + * under /sys/class/net/ however there is no guarantee that they + * are the devices that this process just created. + * 2) Once one of the veth devices is moved to another namespace, it + * is no longer visible in the parent namespace. This seems to + * confuse the name assignment causing it to fail with File exists. + * Because of these issues, this function currently forces the caller + * to fully specify the veth device names. + * + * Returns 0 on success or -1 in case of error + */ +int vethCreate(char* veth1, int veth1MaxLen, + char* veth2, int veth2MaxLen) +{ + int rc = -1; + const char *argv[] = { + "ip", "link", "add", veth1, "type", "veth", "peer", "name", veth2, NULL + }; + int cmdResult; + int vethDev = 0; + + if ((NULL == veth1) || (NULL == veth2)) { + goto error_out; + } + + DEBUG("veth1: %s veth2: %s", veth1, veth2); + + if (1 > strlen(veth1)) { + vethDev = getFreeVethName(veth1, veth1MaxLen, 0); + ++vethDev; + DEBUG("assigned veth1: %s", veth1); + } + + if (1 > strlen(veth2)) { + vethDev = getFreeVethName(veth2, veth2MaxLen, vethDev); + DEBUG("assigned veth2: %s", veth2); + } + + rc = virRun(NULL, (char**)argv, &cmdResult); + + if (0 == rc) { + rc = cmdResult; + } + +error_out: + return rc; +} + +/** + * vethDelete: + * @veth: name for one end of veth pair + * + * This will delete both veth devices in a pair. Only one end needs to + * be specified. The ip command will identify and delete the other veth + * device as well. + * ip link del veth + * + * Returns 0 on success or -1 in case of error + */ +int vethDelete(const char *veth) +{ + int rc = -1; + const char *argv[] = {"ip", "link", "del", veth, NULL}; + int cmdResult; + + if (NULL == veth) { + goto error_out; + } + + DEBUG("veth: %s", veth); + + rc = virRun(NULL, (char**)argv, &cmdResult); + + if (0 == rc) { + rc = cmdResult; + } + +error_out: + return rc; +} + +/** + * vethInterfaceUpOrDown: + * @veth: name of veth device + * @upOrDown: 0 => down, 1 => up + * + * Enables a veth device using the ifconfig command. A NULL inetAddress + * will cause it to be left off the command line. + * + * Returns 0 on success or -1 in case of error + */ +int vethInterfaceUpOrDown(const char* veth, int upOrDown) +{ + int rc = -1; + const char *argv[] = {"ifconfig", veth, NULL, NULL}; + int cmdResult; + + if (NULL == veth) { + goto error_out; + } + + if (0 == upOrDown) + argv[2] = "down"; + else + argv[2] = "up"; + + rc = virRun(NULL, (char**)argv, &cmdResult); + + if (0 == rc) { + rc = cmdResult; + } + +error_out: + return rc; +} + +/** + * moveInterfaceToNetNs: + * @interface: name of device + * @pidInNs: PID of process in target net namespace + * + * Moves the given device into the target net namespace specified by the given + * pid using this command: + * ip link set interface netns pidInNs + * + * Returns 0 on success or -1 in case of error + */ +int moveInterfaceToNetNs(const char* interface, int pidInNs) +{ + int rc; + /* offset of the pid field in the following args */ + char *pid = NULL; + const char *argv[] = { + "ip", "link", "set", interface, "netns", NULL, NULL + }; + int cmdResult; + int len; + + if (NULL == interface) { + goto error_out; + } + + if (asprintf(&pid, "%d", pidInNs) == -1) + goto error_out; + + argv[5] = pid; + rc = virRun(NULL, (char**)argv, &cmdResult); + if (0 == rc) + rc = cmdResult; + +error_out: + VIR_FREE(pid); + return rc; +} diff --git a/src/veth.h b/src/veth.h new file mode 100644 index 0000000000..43181cdee0 --- /dev/null +++ b/src/veth.h @@ -0,0 +1,24 @@ +/* + * veth.h: Interface to tools for managing veth pairs + * + * Copyright IBM Corp. 2008 + * + * See COPYING.LIB for the License of this software + * + * Authors: + * David L. Leskovec + */ + +#ifndef VETH_H +#define VETH_H + +#include + +/* Function declarations */ +int vethCreate(char* veth1, int veth1MaxLen, char* veth2, + int veth2MaxLen); +int vethDelete(const char* veth); +int vethInterfaceUpOrDown(const char* veth, int upOrDown); +int moveInterfaceToNetNs(const char *interface, int pidInNs); + +#endif /* VETH_H */ -- GitLab