1 // Copyright 2021 Google LLC
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //      http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #include "ncsi_sockio.h"
16 
17 #include "common_defs.h"
18 #include "net_iface.h"
19 
20 #include <linux/filter.h>
21 #include <linux/if.h>
22 #include <linux/if_ether.h>
23 #include <netinet/in.h>
24 #include <poll.h>
25 #include <sys/socket.h>
26 
27 #include <cstring>
28 #include <iterator>
29 
30 namespace ncsi
31 {
32 
33 int SockIO::init()
34 {
35     RETURN_IF_ERROR(sockfd_ = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL)),
36                     "ncsi::SockIO::init() failed");
37     return 0;
38 }
39 
40 int SockIO::bind_to_iface(const net::IFaceBase& iface)
41 {
42     iface.set_sock_flags(sockfd_, IFF_PROMISC);
43 
44     std::memset(&sock_addr_, 0, sizeof(sock_addr_));
45 
46     sock_addr_.sll_family = AF_PACKET;
47     sock_addr_.sll_protocol = htons(ETH_P_ALL);
48 
49     RETURN_IF_ERROR(iface.bind_sock(sockfd_, &sock_addr_),
50                     "ncsi::SockIO::bind_to_iface failed");
51 
52     return 0;
53 }
54 
55 /**
56  * Drops VLAN tagged packets from a socket
57  *
58  * ld vlant
59  * jneq #0, drop
60  * ld proto
61  * jneq #0x88f8, drop
62  * ret #-1
63  * drop: ret #0
64  */
65 struct sock_filter vlan_remove_code[] = {
66     {0x20, 0, 0, 0xfffff02c}, {0x15, 0, 3, 0x00000000},
67     {0x20, 0, 0, 0xfffff000}, {0x15, 0, 1, 0x000088f8},
68     {0x6, 0, 0, 0xffffffff},  {0x6, 0, 0, 0x00000000}};
69 
70 struct sock_fprog vlan_remove_bpf = {
71     std::size(vlan_remove_code),
72     vlan_remove_code,
73 };
74 
75 int SockIO::filter_vlans()
76 {
77     return setsockopt(sockfd_, SOL_SOCKET, SO_ATTACH_FILTER, &vlan_remove_bpf,
78                       sizeof(vlan_remove_bpf));
79 }
80 
81 int SockIO::recv(void* buf, size_t maxlen)
82 {
83     struct pollfd sock_pollfd
84     {
85         sockfd_, POLLIN | POLLPRI, 0
86     };
87 
88     int ret = poll(&sock_pollfd, 1, kpoll_timeout_);
89     if (ret > 0)
90     {
91         return ::recv(sockfd_, buf, maxlen, 0);
92     }
93 
94     return ret;
95 }
96 
97 } // namespace ncsi
98