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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,17 @@ | ||
| // SPDX-License-Identifier: Apache-2.0 | ||
| #pragma once | ||
| #include <cstdint> | ||
| #include <stddef.h> | ||
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| struct sockaddr_nl; | ||
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| namespace ebpfdiscovery { | ||
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| class NetlinkCalls { | ||
| public: | ||
| virtual int sendIpAddrRequest(int fd, sockaddr_nl* dst, int domain) const; | ||
| virtual int sendBridgesRequest(int fd, sockaddr_nl* dst, int domain) const; | ||
| virtual int receive(int fd, sockaddr_nl* dst, void* buf, size_t len) const; | ||
| }; | ||
| } // namespace ebpfdiscovery | ||
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,84 @@ | ||
| #include "ebpfdiscovery/NetlinkCalls.h" | ||
| #include <arpa/inet.h> | ||
| #include <array> | ||
| #include <linux/rtnetlink.h> | ||
| #include <net/if.h> | ||
| #include <cstring> | ||
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| namespace ebpfdiscovery { | ||
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| static constexpr uint32_t BUFFLEN{4096}; | ||
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| static void addNetlinkMsg(nlmsghdr* nh, int type, const void* data, int dataLen) { | ||
| struct rtattr* rta; | ||
| int rta_length = RTA_LENGTH(dataLen); | ||
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| rta = reinterpret_cast<rtattr*>((char*)nh + NLMSG_ALIGN(nh->nlmsg_len)); | ||
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| rta->rta_type = type; | ||
| rta->rta_len = rta_length; | ||
| nh->nlmsg_len = NLMSG_ALIGN(nh->nlmsg_len) + RTA_ALIGN(rta_length); | ||
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| memcpy(RTA_DATA(rta), data, dataLen); | ||
| } | ||
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| int NetlinkCalls::sendIpAddrRequest(int fd, sockaddr_nl* dst, int domain) const { | ||
| std::array<char, BUFFLEN> buf{}; | ||
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| nlmsghdr* nl; | ||
| nl = reinterpret_cast<nlmsghdr*>(buf.data()); | ||
| nl->nlmsg_len = NLMSG_LENGTH(sizeof(ifaddrmsg)); | ||
| nl->nlmsg_type = RTM_GETADDR; | ||
| nl->nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT; | ||
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| ifaddrmsg* ifa; | ||
| ifa = reinterpret_cast<ifaddrmsg*>(NLMSG_DATA(nl)); | ||
| ifa->ifa_family = domain; // ipv4 or ipv6 | ||
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| iovec iov = {nl, nl->nlmsg_len}; | ||
| msghdr msg = {dst, sizeof(*dst), &iov, 1, NULL, 0, 0}; | ||
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| return sendmsg(fd, &msg, 0); | ||
| } | ||
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| int NetlinkCalls::sendBridgesRequest(int fd, sockaddr_nl* dst, int domain) const { | ||
| struct { | ||
| struct nlmsghdr n; | ||
| struct ifinfomsg i; | ||
| char _[1024]; // space for rtattr array | ||
| } r{}; | ||
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| const char* dev_type = "bridge"; | ||
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| r.n.nlmsg_len = NLMSG_LENGTH(sizeof(ifinfomsg)); | ||
| r.n.nlmsg_type = RTM_GETLINK; | ||
| r.n.nlmsg_flags = NLM_F_REQUEST | NLM_F_DUMP; | ||
| r.i.ifi_family = AF_PACKET; | ||
| r.n.nlmsg_pid = 0; | ||
| r.n.nlmsg_seq = 0; | ||
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| rtattr* linkinfo = reinterpret_cast<rtattr*>((char*)&r.n + NLMSG_ALIGN(r.n.nlmsg_len)); | ||
| addNetlinkMsg(&r.n, IFLA_LINKINFO, NULL, 0); | ||
| addNetlinkMsg(&r.n, IFLA_INFO_KIND, dev_type, strlen(dev_type) + 1); | ||
| linkinfo->rta_len = (int)(reinterpret_cast<char*>(&r.n) + NLMSG_ALIGN(r.n.nlmsg_len) - reinterpret_cast<char*>(linkinfo)); | ||
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| iovec iov = {&r.n, r.n.nlmsg_len}; | ||
| msghdr msg = {dst, sizeof(*dst), &iov, 1, NULL, 0, 0}; | ||
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| return sendmsg(fd, &msg, 0); | ||
| } | ||
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| int NetlinkCalls::receive(int fd, sockaddr_nl* dst, void* buf, size_t len) const { | ||
| iovec iov; | ||
| msghdr msg{}; | ||
| iov.iov_base = buf; | ||
| iov.iov_len = len; | ||
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| msg.msg_name = dst; | ||
| msg.msg_namelen = sizeof(*dst); | ||
| msg.msg_iov = &iov; | ||
| msg.msg_iovlen = 1; | ||
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| return recvmsg(fd, &msg, 0); | ||
| } | ||
| } // namespace ebpfdiscovery |