1 // Copyright (c) 2020 Intel Corporation. All rights reserved. 2 // 3 // SPDX-License-Identifier: Apache-2.0 AND BSD-3-Clause 4 5 use super::{vnet_hdr_len, MacAddr, Tap, TapError}; 6 use std::net::Ipv4Addr; 7 use std::path::Path; 8 use std::{fs, io}; 9 use thiserror::Error; 10 11 #[derive(Error, Debug)] 12 pub enum Error { 13 #[error("Failed to convert an hexadecimal string into an integer: {0}")] 14 ConvertHexStringToInt(std::num::ParseIntError), 15 #[error("Error related to the multiqueue support (no support TAP side)")] 16 MultiQueueNoTapSupport, 17 #[error("Error related to the multiqueue support (no support device side)")] 18 MultiQueueNoDeviceSupport, 19 #[error("Failed to read the TAP flags from sysfs: {0}")] 20 ReadSysfsTunFlags(io::Error), 21 #[error("Open tap device failed: {0}")] 22 TapOpen(TapError), 23 #[error("Setting tap IP failed: {0}")] 24 TapSetIp(TapError), 25 #[error("Setting tap netmask failed: {0}")] 26 TapSetNetmask(TapError), 27 #[error("Setting MAC address failed: {0}")] 28 TapSetMac(TapError), 29 #[error("Getting MAC address failed: {0}")] 30 TapGetMac(TapError), 31 #[error("Setting vnet header size failed: {0}")] 32 TapSetVnetHdrSize(TapError), 33 #[error("Setting MTU failed: {0}")] 34 TapSetMtu(TapError), 35 #[error("Enabling tap interface failed: {0}")] 36 TapEnable(TapError), 37 } 38 39 type Result<T> = std::result::Result<T, Error>; 40 41 fn check_mq_support(if_name: &Option<&str>, queue_pairs: usize) -> Result<()> { 42 if let Some(tap_name) = if_name { 43 let mq = queue_pairs > 1; 44 let path = format!("/sys/class/net/{tap_name}/tun_flags"); 45 // interface does not exist, check is not required 46 if !Path::new(&path).exists() { 47 return Ok(()); 48 } 49 let tun_flags_str = fs::read_to_string(path).map_err(Error::ReadSysfsTunFlags)?; 50 let tun_flags = u32::from_str_radix(tun_flags_str.trim().trim_start_matches("0x"), 16) 51 .map_err(Error::ConvertHexStringToInt)?; 52 if (tun_flags & net_gen::IFF_MULTI_QUEUE != 0) && !mq { 53 return Err(Error::MultiQueueNoDeviceSupport); 54 } else if (tun_flags & net_gen::IFF_MULTI_QUEUE == 0) && mq { 55 return Err(Error::MultiQueueNoTapSupport); 56 } 57 } 58 Ok(()) 59 } 60 61 /// Create a new virtio network device with the given IP address and 62 /// netmask. 63 pub fn open_tap( 64 if_name: Option<&str>, 65 ip_addr: Option<Ipv4Addr>, 66 netmask: Option<Ipv4Addr>, 67 host_mac: &mut Option<MacAddr>, 68 mtu: Option<u16>, 69 num_rx_q: usize, 70 flags: Option<i32>, 71 ) -> Result<Vec<Tap>> { 72 let mut taps: Vec<Tap> = Vec::new(); 73 let mut ifname: String = String::new(); 74 let vnet_hdr_size = vnet_hdr_len() as i32; 75 76 // In case the tap interface already exists, check if the number of 77 // queues is appropriate. The tap might not support multiqueue while 78 // the number of queues indicates the user expects multiple queues, or 79 // on the contrary, the tap might support multiqueue while the number 80 // of queues indicates the user doesn't expect multiple queues. 81 check_mq_support(&if_name, num_rx_q)?; 82 83 for i in 0..num_rx_q { 84 let tap: Tap; 85 if i == 0 { 86 tap = match if_name { 87 Some(name) => Tap::open_named(name, num_rx_q, flags).map_err(Error::TapOpen)?, 88 None => Tap::new(num_rx_q).map_err(Error::TapOpen)?, 89 }; 90 if let Some(ip) = ip_addr { 91 tap.set_ip_addr(ip).map_err(Error::TapSetIp)?; 92 } 93 if let Some(mask) = netmask { 94 tap.set_netmask(mask).map_err(Error::TapSetNetmask)?; 95 } 96 if let Some(mac) = host_mac { 97 tap.set_mac_addr(*mac).map_err(Error::TapSetMac)? 98 } else { 99 *host_mac = Some(tap.get_mac_addr().map_err(Error::TapGetMac)?) 100 } 101 if let Some(mtu) = mtu { 102 tap.set_mtu(mtu as i32).map_err(Error::TapSetMtu)?; 103 } 104 tap.enable().map_err(Error::TapEnable)?; 105 106 tap.set_vnet_hdr_size(vnet_hdr_size) 107 .map_err(Error::TapSetVnetHdrSize)?; 108 109 ifname = String::from_utf8(tap.get_if_name()).unwrap(); 110 } else { 111 tap = Tap::open_named(ifname.as_str(), num_rx_q, flags).map_err(Error::TapOpen)?; 112 113 tap.set_vnet_hdr_size(vnet_hdr_size) 114 .map_err(Error::TapSetVnetHdrSize)?; 115 } 116 taps.push(tap); 117 } 118 Ok(taps) 119 } 120