Line data Source code
1 : /* This stage disables the "tx-udp-segmentation" offload on the loopback
2 : interface. If left enabled, AF_XDP will drop loopback UDP packets sent
3 : by processes that enable TX segmentation via SOL_UDP/UDP_SEGMENT sockopt
4 : or cmsg.
5 :
6 : TLDR tx-udp-segmentation and AF_XDP are incompatible. */
7 :
8 : #include "configure.h"
9 :
10 : #include <net/if.h>
11 : #include <stdio.h>
12 : #include <unistd.h>
13 : #include <sys/ioctl.h>
14 : #include <sys/stat.h>
15 : #include <linux/if.h>
16 : #include <linux/ethtool.h>
17 : #include <linux/sockios.h>
18 :
19 0 : #define NAME "ethtool-loopback"
20 0 : #define MAX_FEATURES (1024)
21 :
22 : #define UDPSEG_FEATURE "tx-udp-segmentation"
23 : static char const udpseg_feature[] = UDPSEG_FEATURE;
24 :
25 : #define ETHTOOL_CMD_SZ( base_t, data_t, data_len ) ( sizeof(base_t) + (sizeof(data_t)*(data_len)) )
26 :
27 : static int
28 0 : enabled( config_t const * config ) {
29 : /* FIXME support for netns is missing */
30 0 : return !config->development.netns.enabled;
31 0 : }
32 :
33 : static void
34 : init_perm( fd_caps_ctx_t * caps,
35 0 : config_t const * config FD_PARAM_UNUSED ) {
36 0 : fd_caps_check_root( caps, NAME, "disable loopback " UDPSEG_FEATURE " with `ethtool --offload lo " UDPSEG_FEATURE " off`" );
37 0 : }
38 :
39 : /* ethtool_ioctl wraps ioctl(sock,SIOCETHTOOL,"lo",*) */
40 :
41 : static int
42 : ethtool_ioctl( int sock,
43 0 : void * data ) {
44 0 : struct ifreq ifr = {0};
45 0 : strcpy( ifr.ifr_name, "lo" );
46 0 : ifr.ifr_data = data;
47 0 : return ioctl( sock, SIOCETHTOOL, &ifr );
48 0 : }
49 :
50 : /* find_feature_index finds the index of an ethtool feature. */
51 :
52 : static int
53 : find_feature_index( int sock,
54 0 : char const * feature ) {
55 :
56 0 : union {
57 0 : struct ethtool_sset_info r;
58 0 : uchar _[ ETHTOOL_CMD_SZ( struct ethtool_sset_info, uint, 1 ) ];
59 0 : } set_info = { .r = {
60 0 : .cmd = ETHTOOL_GSSET_INFO,
61 0 : .sset_mask = fd_ulong_mask_bit( ETH_SS_FEATURES )
62 0 : } };
63 0 : if( FD_UNLIKELY( ethtool_ioctl( sock, &set_info ) ) ) {
64 0 : FD_LOG_ERR(( "error configuring network device, ioctl(SIOCETHTOOL,ETHTOOL_GSSET_INFO) failed (%i-%s)",
65 0 : errno, fd_io_strerror( errno ) ));
66 0 : }
67 0 : uint const feature_cnt = fd_uint_min( set_info.r.data[0], MAX_FEATURES );
68 :
69 0 : static union {
70 0 : struct ethtool_gstrings r;
71 0 : uchar _[ ETHTOOL_CMD_SZ( struct ethtool_gstrings, uchar, MAX_FEATURES*ETH_GSTRING_LEN ) ];
72 0 : } get_strings;
73 0 : get_strings.r = (struct ethtool_gstrings) {
74 0 : .cmd = ETHTOOL_GSTRINGS,
75 0 : .string_set = ETH_SS_FEATURES,
76 0 : .len = feature_cnt
77 0 : };
78 0 : if( FD_UNLIKELY( ethtool_ioctl( sock, &get_strings ) ) ) {
79 0 : FD_LOG_ERR(( "error configuring network device, ioctl(SIOCETHTOOL,ETHTOOL_GSTRINGS) failed (%i-%s)",
80 0 : errno, fd_io_strerror( errno ) ));
81 0 : }
82 :
83 0 : for( uint j=0UL; j<feature_cnt; j++ ) {
84 0 : uchar const * str = get_strings.r.data + (j*ETH_GSTRING_LEN);
85 0 : if( 0==strncmp( (char const *)str, feature, ETH_GSTRING_LEN ) ) return (int)j;
86 0 : }
87 0 : return -1;
88 0 : }
89 :
90 : /* get_feature_state checks if the ethtool feature at index is set.
91 : Returns 1 if enabled, 0 if disabled. Terminates app on failure. */
92 :
93 : static _Bool
94 : get_feature_state( int sock,
95 0 : int index ) {
96 0 : FD_TEST( index>0 && index<MAX_FEATURES );
97 :
98 0 : union {
99 0 : struct ethtool_gfeatures r;
100 0 : uchar _[ ETHTOOL_CMD_SZ( struct ethtool_gfeatures, struct ethtool_get_features_block, (MAX_FEATURES+31)/32 ) ];
101 0 : } get_features;
102 0 : get_features.r = (struct ethtool_gfeatures) {
103 0 : .cmd = ETHTOOL_GFEATURES,
104 0 : .size = (MAX_FEATURES+31)/32
105 0 : };
106 0 : if( FD_UNLIKELY( ethtool_ioctl( sock, &get_features ) ) ) {
107 0 : FD_LOG_ERR(( "error configuring network device, ioctl(SIOCETHTOOL,ETHTOOL_GFEATURES) failed (%i-%s)",
108 0 : errno, fd_io_strerror( errno ) ));
109 0 : }
110 :
111 0 : uint bucket = (uint)index / 32u;
112 0 : uint offset = (uint)index % 32u;
113 0 : return fd_uint_extract_bit( get_features.r.features[ bucket ].active, (int)offset );
114 0 : }
115 :
116 : /* change_feature updates the ethtool feature at the specified index.
117 : state==1 implies enable, state==0 implies disable. Terminates app on
118 : failure. */
119 :
120 : static void
121 : change_feature( int sock,
122 : int index,
123 0 : _Bool state ) {
124 0 : FD_TEST( index>0 && index<MAX_FEATURES );
125 0 : uint bucket = (uint)index / 32u;
126 0 : uint offset = (uint)index % 32u;
127 :
128 0 : union {
129 0 : struct ethtool_sfeatures r;
130 0 : uchar _[ ETHTOOL_CMD_SZ( struct ethtool_sfeatures, struct ethtool_set_features_block, (MAX_FEATURES+31)/32 ) ];
131 0 : } set_features = {0};
132 0 : set_features.r = (struct ethtool_sfeatures) {
133 0 : .cmd = ETHTOOL_SFEATURES,
134 0 : .size = bucket+1,
135 0 : };
136 :
137 0 : set_features.r.features[ bucket ].valid = 1u<<offset;
138 0 : set_features.r.features[ bucket ].requested = ((uint)state)<<offset;
139 :
140 0 : if( FD_UNLIKELY( ethtool_ioctl( sock, &set_features ) ) ) {
141 0 : FD_LOG_ERR(( "error configuring network device, ioctl(SIOCETHTOOL,ETHTOOL_SFEATURES) failed (%i-%s)",
142 0 : errno, fd_io_strerror( errno ) ));
143 0 : }
144 0 : }
145 :
146 : static void
147 0 : init( config_t * const config FD_PARAM_UNUSED ) {
148 0 : int sock = socket( AF_INET, SOCK_DGRAM, 0 );
149 0 : if( FD_UNLIKELY( sock < 0 ) )
150 0 : FD_LOG_ERR(( "error configuring network device, socket(AF_INET,SOCK_DGRAM,0) failed (%i-%s)",
151 0 : errno, fd_io_strerror( errno ) ));
152 :
153 0 : int feature_idx = find_feature_index( sock, udpseg_feature );
154 0 : if( feature_idx<0 ) return;
155 :
156 0 : FD_LOG_NOTICE(( "RUN: `ethtool --offload lo " UDPSEG_FEATURE " off`" ));
157 :
158 0 : change_feature( sock, feature_idx, 0 ); /* disable */
159 :
160 0 : if( FD_UNLIKELY( close( sock ) ) )
161 0 : FD_LOG_ERR(( "error configuring network device, close() socket failed (%i-%s)", errno, fd_io_strerror( errno ) ));
162 0 : }
163 :
164 : static configure_result_t
165 0 : check( config_t const * config FD_PARAM_UNUSED ) {
166 0 : int sock = socket( AF_INET, SOCK_DGRAM, 0 );
167 0 : if( FD_UNLIKELY( sock < 0 ) )
168 0 : FD_LOG_ERR(( "error configuring network device, socket(AF_INET,SOCK_DGRAM,0) failed (%i-%s)",
169 0 : errno, fd_io_strerror( errno ) ));
170 :
171 0 : int feature_idx = find_feature_index( sock, udpseg_feature );
172 0 : if( feature_idx<0 ) {
173 0 : FD_LOG_INFO(( "device `lo` missing ethtool offload `" UDPSEG_FEATURE "`, ignoring" ));
174 0 : CONFIGURE_OK(); /* returns */
175 0 : }
176 :
177 0 : _Bool udpseg_enabled = get_feature_state( sock, feature_idx );
178 :
179 0 : if( FD_UNLIKELY( close( sock ) ) )
180 0 : FD_LOG_ERR(( "error configuring network device, close() socket failed (%i-%s)", errno, fd_io_strerror( errno ) ));
181 :
182 0 : if( udpseg_enabled ) {
183 0 : NOT_CONFIGURED( "device `lo` has " UDPSEG_FEATURE " enabled. Should be disabled" );
184 0 : }
185 :
186 0 : CONFIGURE_OK();
187 0 : }
188 :
189 : configure_stage_t fd_cfg_stage_ethtool_loopback = {
190 : .name = NAME,
191 : .always_recreate = 0,
192 : .enabled = enabled,
193 : .init_perm = init_perm,
194 : .fini_perm = NULL,
195 : .init = init,
196 : .fini = NULL,
197 : .check = check,
198 : };
199 :
200 : #undef NAME
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