├── .gitignore ├── LICENSE ├── Makefile ├── README.md ├── network_client.c ├── network_server.c ├── testing.c └── todo.txt /.gitignore: -------------------------------------------------------------------------------- 1 | # Object files 2 | *.o 3 | *.ko 4 | *.obj 5 | *.elf 6 | *.cmd 7 | 8 | # Precompiled Headers 9 | *.gch 10 | *.pch 11 | 12 | # Libraries 13 | *.lib 14 | *.a 15 | *.la 16 | *.lo 17 | 18 | # Shared objects (inc. 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Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | {one line to give the program's name and a brief idea of what it does.} 635 | Copyright (C) {year} {name of author} 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see . 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | {project} Copyright (C) {year} {fullname} 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | . 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | . 675 | -------------------------------------------------------------------------------- /Makefile: -------------------------------------------------------------------------------- 1 | obj-m += network_client.o 2 | obj-m += network_server.o 3 | 4 | all: 5 | make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules 6 | clean: 7 | make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean 8 | 9 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # simple-linux-kernel-tcp-client-server 2 | A simple in-kernel tcp client and server implemented as LKMs (linux kernel 3 | version 4.1.3) 4 | 5 | This is an attempt to build a tcp server, entirely in kernel space, that supports mulitple tcp clients. The tcp client is also entirely in kernel space. 6 | 7 | The client and server are built as loadable kernel modules. 8 | 9 | **To try this out:** 10 | 11 | 1. clone this repo to server machine. 12 | 2. open network_server.c 13 | * change the port number of your server. 14 | * sorry, this will soon be changed to module parameter. 15 | 3. make 16 | 4. sudo insmod network_server.ko 17 | 5. keep observing dmesg out. 18 | 6. clone this repo to client machine. 19 | 7. before inserting the client, open network_client.c 20 | * change the ip and port number to that of your server. 21 | * again, this too will soon be changed to module parameters. 22 | 8. make 23 | 9. sudo insmod network_client.ko 24 | 25 | **Status:** 26 | 27 | Work almost done. 28 | -------------------------------------------------------------------------------- /network_client.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | 5 | #include 6 | #include 7 | #include 8 | #include 9 | #include 10 | #include 11 | #include 12 | 13 | MODULE_LICENSE("GPL"); 14 | MODULE_AUTHOR("Aby Sam Ross"); 15 | 16 | #define PORT 2325 17 | 18 | struct socket *conn_socket = NULL; 19 | 20 | u32 create_address(u8 *ip) 21 | { 22 | u32 addr = 0; 23 | int i; 24 | 25 | for(i=0; i<4; i++) 26 | { 27 | addr += ip[i]; 28 | if(i==3) 29 | break; 30 | addr <<= 8; 31 | } 32 | return addr; 33 | } 34 | 35 | int tcp_client_send(struct socket *sock, const char *buf, const size_t length,\ 36 | unsigned long flags) 37 | { 38 | struct msghdr msg; 39 | //struct iovec iov; 40 | struct kvec vec; 41 | int len, written = 0, left = length; 42 | mm_segment_t oldmm; 43 | 44 | msg.msg_name = 0; 45 | msg.msg_namelen = 0; 46 | /* 47 | msg.msg_iov = &iov; 48 | msg.msg_iovlen = 1; 49 | */ 50 | msg.msg_control = NULL; 51 | msg.msg_controllen = 0; 52 | msg.msg_flags = flags; 53 | 54 | oldmm = get_fs(); set_fs(KERNEL_DS); 55 | repeat_send: 56 | /* 57 | msg.msg_iov->iov_len = left; 58 | msg.msg_iov->iov_base = (char *)buf + written; 59 | */ 60 | vec.iov_len = left; 61 | vec.iov_base = (char *)buf + written; 62 | 63 | //len = sock_sendmsg(sock, &msg, left); 64 | len = kernel_sendmsg(sock, &msg, &vec, left, left); 65 | if((len == -ERESTARTSYS) || (!(flags & MSG_DONTWAIT) &&\ 66 | (len == -EAGAIN))) 67 | goto repeat_send; 68 | if(len > 0) 69 | { 70 | written += len; 71 | left -= len; 72 | if(left) 73 | goto repeat_send; 74 | } 75 | set_fs(oldmm); 76 | return written ? written:len; 77 | } 78 | 79 | int tcp_client_receive(struct socket *sock, char *str,\ 80 | unsigned long flags) 81 | { 82 | //mm_segment_t oldmm; 83 | struct msghdr msg; 84 | //struct iovec iov; 85 | struct kvec vec; 86 | int len; 87 | int max_size = 50; 88 | 89 | msg.msg_name = 0; 90 | msg.msg_namelen = 0; 91 | /* 92 | msg.msg_iov = &iov; 93 | msg.msg_iovlen = 1; 94 | */ 95 | msg.msg_control = NULL; 96 | msg.msg_controllen = 0; 97 | msg.msg_flags = flags; 98 | /* 99 | msg.msg_iov->iov_base = str; 100 | msg.msg_ioc->iov_len = max_size; 101 | */ 102 | vec.iov_len = max_size; 103 | vec.iov_base = str; 104 | 105 | //oldmm = get_fs(); set_fs(KERNEL_DS); 106 | read_again: 107 | //len = sock_recvmsg(sock, &msg, max_size, 0); 108 | len = kernel_recvmsg(sock, &msg, &vec, max_size, max_size, flags); 109 | 110 | if(len == -EAGAIN || len == -ERESTARTSYS) 111 | { 112 | pr_info(" *** mtp | error while reading: %d | " 113 | "tcp_client_receive *** \n", len); 114 | 115 | goto read_again; 116 | } 117 | 118 | 119 | pr_info(" *** mtp | the server says: %s | tcp_client_receive *** \n", str); 120 | //set_fs(oldmm); 121 | return len; 122 | } 123 | 124 | int tcp_client_connect(void) 125 | { 126 | struct sockaddr_in saddr; 127 | /* 128 | struct sockaddr_in daddr; 129 | struct socket *data_socket = NULL; 130 | */ 131 | unsigned char destip[5] = {10,129,41,200,'\0'}; 132 | /* 133 | char *response = kmalloc(4096, GFP_KERNEL); 134 | char *reply = kmalloc(4096, GFP_KERNEL); 135 | */ 136 | int len = 49; 137 | char response[len+1]; 138 | char reply[len+1]; 139 | int ret = -1; 140 | 141 | //DECLARE_WAITQUEUE(recv_wait, current); 142 | DECLARE_WAIT_QUEUE_HEAD(recv_wait); 143 | 144 | ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &conn_socket); 145 | if(ret < 0) 146 | { 147 | pr_info(" *** mtp | Error: %d while creating first socket. | " 148 | "setup_connection *** \n", ret); 149 | goto err; 150 | } 151 | 152 | memset(&saddr, 0, sizeof(saddr)); 153 | saddr.sin_family = AF_INET; 154 | saddr.sin_port = htons(PORT); 155 | saddr.sin_addr.s_addr = htonl(create_address(destip)); 156 | 157 | ret = conn_socket->ops->connect(conn_socket, (struct sockaddr *)&saddr\ 158 | , sizeof(saddr), O_RDWR); 159 | if(ret && (ret != -EINPROGRESS)) 160 | { 161 | pr_info(" *** mtp | Error: %d while connecting using conn " 162 | "socket. | setup_connection *** \n", ret); 163 | goto err; 164 | } 165 | 166 | memset(&reply, 0, len+1); 167 | strcat(reply, "HOLA"); 168 | tcp_client_send(conn_socket, reply, strlen(reply), MSG_DONTWAIT); 169 | 170 | wait_event_timeout(recv_wait,\ 171 | !skb_queue_empty(&conn_socket->sk->sk_receive_queue),\ 172 | 5*HZ); 173 | /* 174 | add_wait_queue(&conn_socket->sk->sk_wq->wait, &recv_wait); 175 | while(1) 176 | { 177 | __set_current_status(TASK_INTERRUPTIBLE); 178 | schedule_timeout(HZ); 179 | */ 180 | if(!skb_queue_empty(&conn_socket->sk->sk_receive_queue)) 181 | { 182 | /* 183 | __set_current_status(TASK_RUNNING); 184 | remove_wait_queue(&conn_socket->sk->sk_wq->wait,\ 185 | &recv_wait); 186 | */ 187 | memset(&response, 0, len+1); 188 | tcp_client_receive(conn_socket, response, MSG_DONTWAIT); 189 | //break; 190 | } 191 | 192 | /* 193 | } 194 | */ 195 | 196 | err: 197 | return -1; 198 | } 199 | 200 | static int __init network_client_init(void) 201 | { 202 | pr_info(" *** mtp | network client init | network_client_init *** \n"); 203 | tcp_client_connect(); 204 | return 0; 205 | } 206 | 207 | static void __exit network_client_exit(void) 208 | { 209 | int len = 49; 210 | char response[len+1]; 211 | char reply[len+1]; 212 | 213 | //DECLARE_WAITQUEUE(exit_wait, current); 214 | DECLARE_WAIT_QUEUE_HEAD(exit_wait); 215 | 216 | memset(&reply, 0, len+1); 217 | strcat(reply, "ADIOS"); 218 | //tcp_client_send(conn_socket, reply); 219 | tcp_client_send(conn_socket, reply, strlen(reply), MSG_DONTWAIT); 220 | 221 | //while(1) 222 | //{ 223 | /* 224 | tcp_client_receive(conn_socket, response); 225 | add_wait_queue(&conn_socket->sk->sk_wq->wait, &exit_wait) 226 | */ 227 | wait_event_timeout(exit_wait,\ 228 | !skb_queue_empty(&conn_socket->sk->sk_receive_queue),\ 229 | 5*HZ); 230 | if(!skb_queue_empty(&conn_socket->sk->sk_receive_queue)) 231 | { 232 | memset(&response, 0, len+1); 233 | tcp_client_receive(conn_socket, response, MSG_DONTWAIT); 234 | //remove_wait_queue(&conn_socket->sk->sk_wq->wait, &exit_wait); 235 | } 236 | 237 | //} 238 | 239 | if(conn_socket != NULL) 240 | { 241 | sock_release(conn_socket); 242 | } 243 | pr_info(" *** mtp | network client exiting | network_client_exit *** \n"); 244 | } 245 | 246 | module_init(network_client_init) 247 | module_exit(network_client_exit) 248 | -------------------------------------------------------------------------------- /network_server.c: -------------------------------------------------------------------------------- 1 | #include 2 | #include 3 | #include 4 | #include 5 | #include 6 | 7 | #include 8 | #include 9 | 10 | #include 11 | #include 12 | #include 13 | 14 | #include 15 | #include 16 | 17 | #include 18 | #include 19 | #include 20 | #include 21 | 22 | #define DEFAULT_PORT 2325 23 | #define MODULE_NAME "tmem_tcp_server" 24 | #define MAX_CONNS 16 25 | 26 | MODULE_LICENSE("GPL"); 27 | MODULE_AUTHOR("Aby Sam Ross"); 28 | 29 | static int tcp_listener_stopped = 0; 30 | static int tcp_acceptor_stopped = 0; 31 | 32 | DEFINE_SPINLOCK(tcp_server_lock); 33 | 34 | struct tcp_conn_handler_data 35 | { 36 | struct sockaddr_in *address; 37 | struct socket *accept_socket; 38 | int thread_id; 39 | }; 40 | 41 | struct tcp_conn_handler 42 | { 43 | struct tcp_conn_handler_data *data[MAX_CONNS]; 44 | struct task_struct *thread[MAX_CONNS]; 45 | int tcp_conn_handler_stopped[MAX_CONNS]; 46 | }; 47 | 48 | struct tcp_conn_handler *tcp_conn_handler; 49 | 50 | 51 | struct tcp_server_service 52 | { 53 | int running; 54 | struct socket *listen_socket; 55 | struct task_struct *thread; 56 | struct task_struct *accept_thread; 57 | }; 58 | 59 | struct tcp_server_service *tcp_server; 60 | 61 | char *inet_ntoa(struct in_addr *in) 62 | { 63 | char *str_ip = NULL; 64 | u_int32_t int_ip = 0; 65 | 66 | str_ip = kmalloc(16 * sizeof(char), GFP_KERNEL); 67 | 68 | if(!str_ip) 69 | return NULL; 70 | else 71 | memset(str_ip, 0, 16); 72 | 73 | int_ip = in->s_addr; 74 | 75 | sprintf(str_ip, "%d.%d.%d.%d", (int_ip) & 0xFF, (int_ip >> 8) & 0xFF, 76 | (int_ip >> 16) & 0xFF, (int_ip >> 16) & 0xFF); 77 | 78 | return str_ip; 79 | } 80 | 81 | int tcp_server_send(struct socket *sock, int id, const char *buf,\ 82 | const size_t length, unsigned long flags) 83 | { 84 | struct msghdr msg; 85 | struct kvec vec; 86 | int len, written = 0, left =length; 87 | mm_segment_t oldmm; 88 | 89 | msg.msg_name = 0; 90 | msg.msg_namelen = 0; 91 | msg.msg_control = NULL; 92 | msg.msg_controllen = 0; 93 | msg.msg_flags = flags; 94 | msg.msg_flags = 0; 95 | 96 | oldmm = get_fs(); set_fs(KERNEL_DS); 97 | 98 | repeat_send: 99 | vec.iov_len = left; 100 | vec.iov_base = (char *)buf + written; 101 | 102 | len = kernel_sendmsg(sock, &msg, &vec, left, left); 103 | 104 | if((len == -ERESTARTSYS) || (!(flags & MSG_DONTWAIT) &&\ 105 | (len == -EAGAIN))) 106 | goto repeat_send; 107 | 108 | if(len > 0) 109 | { 110 | written += len; 111 | left -= len; 112 | if(left) 113 | goto repeat_send; 114 | } 115 | 116 | set_fs(oldmm); 117 | return written?written:len; 118 | } 119 | 120 | int tcp_server_receive(struct socket *sock, int id,struct sockaddr_in *address,\ 121 | unsigned char *buf,int size, unsigned long flags) 122 | { 123 | struct msghdr msg; 124 | struct kvec vec; 125 | int len; 126 | char *tmp = NULL; 127 | 128 | if(sock==NULL) 129 | { 130 | pr_info(" *** mtp | tcp server receive socket is NULL| " 131 | " tcp_server_receive *** \n"); 132 | return -1; 133 | } 134 | 135 | msg.msg_name = 0; 136 | msg.msg_namelen = 0; 137 | msg.msg_control = NULL; 138 | msg.msg_controllen = 0; 139 | msg.msg_flags = flags; 140 | 141 | vec.iov_len = size; 142 | vec.iov_base = buf; 143 | 144 | read_again: 145 | 146 | /* 147 | if(kthread_should_stop()) 148 | { 149 | pr_info(" *** mtp | tcp server handle connection thread " 150 | "stopped | tcp_server_receive *** \n"); 151 | //tcp_conn_handler->thread[id] = NULL; 152 | tcp_conn_handler->tcp_conn_handler_stopped[id]= 1; 153 | //sock_release(sock); 154 | do_exit(0); 155 | } 156 | */ 157 | 158 | if(!skb_queue_empty(&sock->sk->sk_receive_queue)) 159 | pr_info("recv queue empty ? %s \n", 160 | skb_queue_empty(&sock->sk->sk_receive_queue)?"yes":"no"); 161 | 162 | len = kernel_recvmsg(sock, &msg, &vec, size, size, flags); 163 | 164 | if(len == -EAGAIN || len == -ERESTARTSYS) 165 | goto read_again; 166 | 167 | tmp = inet_ntoa(&(address->sin_addr)); 168 | 169 | pr_info("client-> %s:%d, says: %s\n", tmp, ntohs(address->sin_port), buf); 170 | 171 | kfree(tmp); 172 | //len = msg.msg_iter.kvec->iov_len; 173 | return len; 174 | } 175 | 176 | int connection_handler(void *data) 177 | { 178 | struct tcp_conn_handler_data *conn_data = 179 | (struct tcp_conn_handler_data *)data; 180 | 181 | struct sockaddr_in *address = conn_data->address; 182 | struct socket *accept_socket = conn_data->accept_socket; 183 | int id = conn_data->thread_id; 184 | 185 | int ret; 186 | int len = 49; 187 | unsigned char in_buf[len+1]; 188 | unsigned char out_buf[len+1]; 189 | //char *tmp; 190 | 191 | DECLARE_WAITQUEUE(recv_wait, current); 192 | allow_signal(SIGKILL|SIGSTOP); 193 | 194 | 195 | /* 196 | while((ret = tcp_server_receive(accept_socket, id, in_buf, len,\ 197 | MSG_DONTWAIT))) 198 | while(tcp_server_receive(accept_socket, id, in_buf, len,\ 199 | MSG_DONTWAIT)) 200 | */ 201 | while(1) 202 | { 203 | /* 204 | if(kthread_should_stop()) 205 | { 206 | pr_info(" *** mtp | tcp server acceptor thread " 207 | "stopped | tcp_server_accept *** \n"); 208 | tcp_acceptor_stopped = 1; 209 | do_exit(0); 210 | } 211 | if(ret == 0) 212 | */ 213 | 214 | add_wait_queue(&accept_socket->sk->sk_wq->wait, &recv_wait); 215 | 216 | while(skb_queue_empty(&accept_socket->sk->sk_receive_queue)) 217 | { 218 | __set_current_state(TASK_INTERRUPTIBLE); 219 | schedule_timeout(HZ); 220 | 221 | if(kthread_should_stop()) 222 | { 223 | pr_info(" *** mtp | tcp server handle connection " 224 | "thread stopped | connection_handler *** \n"); 225 | 226 | //tcp_conn_handler->thread[id] = NULL; 227 | tcp_conn_handler->tcp_conn_handler_stopped[id]= 1; 228 | 229 | __set_current_state(TASK_RUNNING); 230 | remove_wait_queue(&accept_socket->sk->sk_wq->wait,\ 231 | &recv_wait); 232 | kfree(tcp_conn_handler->data[id]->address); 233 | kfree(tcp_conn_handler->data[id]); 234 | sock_release(tcp_conn_handler->data[id]->accept_socket); 235 | /* 236 | tcp_conn_handler->thread[id] = NULL; 237 | sock_release(sock); 238 | do_exit(0); 239 | */ 240 | return 0; 241 | } 242 | 243 | if(signal_pending(current)) 244 | { 245 | __set_current_state(TASK_RUNNING); 246 | remove_wait_queue(&accept_socket->sk->sk_wq->wait,\ 247 | &recv_wait); 248 | /* 249 | kfree(tcp_conn_handler->data[id]->address); 250 | kfree(tcp_conn_handler->data[id]); 251 | sock_release(tcp_conn_handler->data[id]->accept_socket); 252 | */ 253 | goto out; 254 | } 255 | } 256 | __set_current_state(TASK_RUNNING); 257 | remove_wait_queue(&accept_socket->sk->sk_wq->wait, &recv_wait); 258 | 259 | 260 | pr_info("receiving message\n"); 261 | memset(in_buf, 0, len+1); 262 | ret = tcp_server_receive(accept_socket, id, address, in_buf, len,\ 263 | MSG_DONTWAIT); 264 | if(ret > 0) 265 | { 266 | if(memcmp(in_buf, "HOLA", 4) == 0) 267 | { 268 | memset(out_buf, 0, len+1); 269 | strcat(out_buf, "HOLASI"); 270 | pr_info("sending response: %s\n", out_buf); 271 | tcp_server_send(accept_socket, id, out_buf,\ 272 | strlen(out_buf), MSG_DONTWAIT); 273 | } 274 | /* 275 | tmp = inet_ntoa(&(address->sin_addr)); 276 | pr_info("connection handler: %d of: %s %d done sending " 277 | " HOLASI\n", id, tmp, ntohs(address->sin_port)); 278 | kfree(tmp); 279 | */ 280 | if(memcmp(in_buf, "ADIOS", 5) == 0) 281 | { 282 | memset(out_buf, 0, len+1); 283 | strcat(out_buf, "ADIOSAMIGO"); 284 | pr_info("sending response: %s\n", out_buf); 285 | tcp_server_send(accept_socket, id, out_buf,\ 286 | strlen(out_buf), MSG_DONTWAIT); 287 | break; 288 | } 289 | } 290 | } 291 | 292 | out: 293 | /* 294 | tmp = inet_ntoa(&(address->sin_addr)); 295 | 296 | pr_info("connection handler: %d of: %s %d exiting normally\n", 297 | id, tmp, ntohs(address->sin_port)); 298 | kfree(tmp); 299 | */ 300 | tcp_conn_handler->tcp_conn_handler_stopped[id]= 1; 301 | kfree(tcp_conn_handler->data[id]->address); 302 | kfree(tcp_conn_handler->data[id]); 303 | sock_release(tcp_conn_handler->data[id]->accept_socket); 304 | //spin_lock(&tcp_server_lock); 305 | tcp_conn_handler->thread[id] = NULL; 306 | //spin_unlock(&tcp_server_lock); 307 | //return 0; 308 | do_exit(0); 309 | } 310 | 311 | int tcp_server_accept(void) 312 | { 313 | int accept_err = 0; 314 | struct socket *socket; 315 | struct socket *accept_socket = NULL; 316 | struct inet_connection_sock *isock; 317 | int id = 0; 318 | /* 319 | int len = 49; 320 | unsigned char in_buf[len+1]; 321 | unsigned char out_buf[len+1]; 322 | */ 323 | DECLARE_WAITQUEUE(accept_wait, current); 324 | /* 325 | spin_lock(&tcp_server_lock); 326 | tcp_server->running = 1; 327 | current->flags |= PF_NOFREEZE; 328 | */ 329 | allow_signal(SIGKILL|SIGSTOP); 330 | //spin_unlock(&tcp_server_lock); 331 | 332 | socket = tcp_server->listen_socket; 333 | pr_info(" *** mtp | creating the accept socket | tcp_server_accept " 334 | "*** \n"); 335 | /* 336 | accept_socket = 337 | (struct socket*)kmalloc(sizeof(struct socket), GFP_KERNEL); 338 | */ 339 | 340 | while(1) 341 | { 342 | struct tcp_conn_handler_data *data = NULL; 343 | struct sockaddr_in *client = NULL; 344 | char *tmp; 345 | int addr_len; 346 | 347 | accept_err = 348 | sock_create(socket->sk->sk_family, socket->type,\ 349 | socket->sk->sk_protocol, &accept_socket); 350 | /* 351 | sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP,\ 352 | &accept_socket); 353 | */ 354 | 355 | if(accept_err < 0 || !accept_socket) 356 | { 357 | pr_info(" *** mtp | accept_error: %d while creating " 358 | "tcp server accept socket | " 359 | "tcp_server_accept *** \n", accept_err); 360 | goto err; 361 | } 362 | 363 | accept_socket->type = socket->type; 364 | accept_socket->ops = socket->ops; 365 | 366 | isock = inet_csk(socket->sk); 367 | 368 | //while(1) 369 | //{ 370 | /* 371 | struct tcp_conn_handler_data *data = NULL; 372 | struct sockaddr_in *client = NULL; 373 | char *tmp; 374 | int addr_len; 375 | */ 376 | 377 | add_wait_queue(&socket->sk->sk_wq->wait, &accept_wait); 378 | while(reqsk_queue_empty(&isock->icsk_accept_queue)) 379 | { 380 | __set_current_state(TASK_INTERRUPTIBLE); 381 | //set_current_state(TASK_INTERRUPTIBLE); 382 | 383 | //change this HZ to about 5 mins in jiffies 384 | schedule_timeout(HZ); 385 | 386 | //pr_info("icsk queue empty ? %s \n", 387 | //reqsk_queue_empty(&isock->icsk_accept_queue)?"yes":"no"); 388 | 389 | //pr_info("recv queue empty ? %s \n", 390 | //skb_queue_empty(&socket->sk->sk_receive_queue)?"yes":"no"); 391 | if(kthread_should_stop()) 392 | { 393 | pr_info(" *** mtp | tcp server acceptor thread " 394 | "stopped | tcp_server_accept *** \n"); 395 | tcp_acceptor_stopped = 1; 396 | __set_current_state(TASK_RUNNING); 397 | remove_wait_queue(&socket->sk->sk_wq->wait,\ 398 | &accept_wait); 399 | sock_release(accept_socket); 400 | //do_exit(0); 401 | return 0; 402 | } 403 | 404 | if(signal_pending(current)) 405 | { 406 | __set_current_state(TASK_RUNNING); 407 | remove_wait_queue(&socket->sk->sk_wq->wait,\ 408 | &accept_wait); 409 | goto release; 410 | } 411 | 412 | } 413 | __set_current_state(TASK_RUNNING); 414 | remove_wait_queue(&socket->sk->sk_wq->wait, &accept_wait); 415 | 416 | pr_info("accept connection\n"); 417 | 418 | accept_err = 419 | socket->ops->accept(socket, accept_socket, O_NONBLOCK); 420 | 421 | if(accept_err < 0) 422 | { 423 | pr_info(" *** mtp | accept_error: %d while accepting " 424 | "tcp server | tcp_server_accept *** \n", 425 | accept_err); 426 | goto release; 427 | } 428 | 429 | client = kmalloc(sizeof(struct sockaddr_in), GFP_KERNEL); 430 | memset(client, 0, sizeof(struct sockaddr_in)); 431 | 432 | addr_len = sizeof(struct sockaddr_in); 433 | 434 | accept_err = 435 | accept_socket->ops->getname(accept_socket,\ 436 | (struct sockaddr *)client,\ 437 | &addr_len, 2); 438 | 439 | if(accept_err < 0) 440 | { 441 | pr_info(" *** mtp | accept_error: %d in getname " 442 | "tcp server | tcp_server_accept *** \n", 443 | accept_err); 444 | goto release; 445 | } 446 | 447 | 448 | tmp = inet_ntoa(&(client->sin_addr)); 449 | 450 | pr_info("connection from: %s %d \n", 451 | tmp, ntohs(client->sin_port)); 452 | 453 | kfree(tmp); 454 | 455 | /* 456 | memset(in_buf, 0, len+1); 457 | pr_info("receive the package\n"); 458 | */ 459 | pr_info("handle connection\n"); 460 | 461 | /* 462 | while((accept_err = tcp_server_receive(accept_socket, in_buf,\ 463 | len, MSG_DONTWAIT))) 464 | {*/ 465 | /* not needed here 466 | if(kthread_should_stop()) 467 | { 468 | pr_info(" *** mtp | tcp server acceptor thread " 469 | "stopped | tcp_server_accept *** \n"); 470 | tcp_acceptor_stopped = 1; 471 | do_exit(0); 472 | } 473 | */ 474 | /* 475 | if(accept_err == 0) 476 | continue; 477 | 478 | memset(out_buf, 0, len+1); 479 | strcat(out_buf, "kernel server: hi"); 480 | pr_info("sending the package\n"); 481 | tcp_server_send(accept_socket, out_buf, strlen(out_buf),\ 482 | MSG_DONTWAIT); 483 | } 484 | */ 485 | 486 | /*should I protect this against concurrent access?*/ 487 | for(id = 0; id < MAX_CONNS; id++) 488 | { 489 | //spin_lock(&tcp_server_lock); 490 | if(tcp_conn_handler->thread[id] == NULL) 491 | break; 492 | //spin_unlock(&tcp_server_lock); 493 | } 494 | 495 | pr_info("gave free id: %d\n", id); 496 | 497 | if(id == MAX_CONNS) 498 | goto release; 499 | 500 | data = kmalloc(sizeof(struct tcp_conn_handler_data), GFP_KERNEL); 501 | memset(data, 0, sizeof(struct tcp_conn_handler_data)); 502 | 503 | data->address = client; 504 | data->accept_socket = accept_socket; 505 | data->thread_id = id; 506 | 507 | tcp_conn_handler->tcp_conn_handler_stopped[id] = 0; 508 | tcp_conn_handler->data[id] = data; 509 | tcp_conn_handler->thread[id] = 510 | kthread_run((void *)connection_handler, (void *)data, MODULE_NAME); 511 | 512 | if(kthread_should_stop()) 513 | { 514 | pr_info(" *** mtp | tcp server acceptor thread stopped" 515 | " | tcp_server_accept *** \n"); 516 | tcp_acceptor_stopped = 1; 517 | /* 518 | kfree(tcp_conn_handler->data[id]->address); 519 | kfree(tcp_conn_handler->data[id]); 520 | sock_release(tcp_conn_handler->data[id]->accept_socket); 521 | kfree(accept_socket); 522 | do_exit(0); 523 | */ 524 | return 0; 525 | } 526 | 527 | if(signal_pending(current)) 528 | { 529 | /* 530 | kfree(tcp_conn_handler->data[id]->address); 531 | kfree(tcp_conn_handler->data[id]); 532 | goto err; 533 | */ 534 | break; 535 | } 536 | //} 537 | } 538 | 539 | /* 540 | kfree(tcp_conn_handler->data[id]->address); 541 | kfree(tcp_conn_handler->data[id]); 542 | sock_release(tcp_conn_handler->data[id]->accept_socket); 543 | */ 544 | tcp_acceptor_stopped = 1; 545 | //return 0; 546 | do_exit(0); 547 | release: 548 | sock_release(accept_socket); 549 | err: 550 | tcp_acceptor_stopped = 1; 551 | //return -1; 552 | do_exit(0); 553 | } 554 | 555 | int tcp_server_listen(void) 556 | { 557 | int server_err; 558 | struct socket *conn_socket; 559 | struct sockaddr_in server; 560 | 561 | DECLARE_WAIT_QUEUE_HEAD(wq); 562 | 563 | //spin_lock(&tcp_server_lock); 564 | //tcp_server->running = 1; 565 | allow_signal(SIGKILL|SIGTERM); 566 | //spin_unlock(&tcp_server_lock); 567 | 568 | server_err = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP,\ 569 | &tcp_server->listen_socket); 570 | if(server_err < 0) 571 | { 572 | pr_info(" *** mtp | Error: %d while creating tcp server " 573 | "listen socket | tcp_server_listen *** \n", server_err); 574 | goto err; 575 | } 576 | 577 | conn_socket = tcp_server->listen_socket; 578 | tcp_server->listen_socket->sk->sk_reuse = 1; 579 | 580 | //server.sin_addr.s_addr = htonl(INADDR_ANY); 581 | server.sin_addr.s_addr = INADDR_ANY; 582 | server.sin_family = AF_INET; 583 | server.sin_port = htons(DEFAULT_PORT); 584 | 585 | server_err = 586 | conn_socket->ops->bind(conn_socket, (struct sockaddr*)&server,\ 587 | sizeof(server)); 588 | 589 | if(server_err < 0) 590 | { 591 | pr_info(" *** mtp | Error: %d while binding tcp server " 592 | "listen socket | tcp_server_listen *** \n", server_err); 593 | goto release; 594 | } 595 | 596 | //while(1) 597 | //{ 598 | server_err = conn_socket->ops->listen(conn_socket, 16); 599 | 600 | if(server_err < 0) 601 | { 602 | pr_info(" *** mtp | Error: %d while listening in tcp " 603 | "server listen socket | tcp_server_listen " 604 | "*** \n", server_err); 605 | goto release; 606 | } 607 | 608 | tcp_server->accept_thread = 609 | kthread_run((void*)tcp_server_accept, NULL, MODULE_NAME); 610 | 611 | while(1) 612 | { 613 | wait_event_timeout(wq, 0, 3*HZ); 614 | 615 | if(kthread_should_stop()) 616 | { 617 | pr_info(" *** mtp | tcp server listening thread" 618 | " stopped | tcp_server_listen *** \n"); 619 | /* 620 | tcp_listener_stopped = 1; 621 | sock_release(conn_socket); 622 | do_exit(0); 623 | */ 624 | return 0; 625 | } 626 | 627 | if(signal_pending(current)) 628 | goto release; 629 | } 630 | //} 631 | 632 | sock_release(conn_socket); 633 | tcp_listener_stopped = 1; 634 | //return 0; 635 | do_exit(0); 636 | release: 637 | sock_release(conn_socket); 638 | err: 639 | tcp_listener_stopped = 1; 640 | //return -1; 641 | do_exit(0); 642 | } 643 | 644 | int tcp_server_start(void) 645 | { 646 | tcp_server->running = 1; 647 | tcp_server->thread = kthread_run((void *)tcp_server_listen, NULL,\ 648 | MODULE_NAME); 649 | return 0; 650 | } 651 | 652 | static int __init network_server_init(void) 653 | { 654 | pr_info(" *** mtp | network_server initiated | " 655 | "network_server_init ***\n"); 656 | tcp_server = kmalloc(sizeof(struct tcp_server_service), GFP_KERNEL); 657 | memset(tcp_server, 0, sizeof(struct tcp_server_service)); 658 | 659 | tcp_conn_handler = kmalloc(sizeof(struct tcp_conn_handler), GFP_KERNEL); 660 | memset(tcp_conn_handler, 0, sizeof(struct tcp_conn_handler)); 661 | 662 | tcp_server_start(); 663 | return 0; 664 | } 665 | 666 | static void __exit network_server_exit(void) 667 | { 668 | int ret; 669 | int id; 670 | 671 | if(tcp_server->thread == NULL) 672 | pr_info(" *** mtp | No kernel thread to kill | " 673 | "network_server_exit *** \n"); 674 | else 675 | { 676 | for(id = 0; id < MAX_CONNS; id++) 677 | { 678 | if(tcp_conn_handler->thread[id] != NULL) 679 | { 680 | 681 | if(!tcp_conn_handler->tcp_conn_handler_stopped[id]) 682 | { 683 | ret = 684 | kthread_stop(tcp_conn_handler->thread[id]); 685 | 686 | if(!ret) 687 | pr_info(" *** mtp | tcp server " 688 | "connection handler thread: %d " 689 | "stopped | network_server_exit " 690 | "*** \n", id); 691 | } 692 | } 693 | } 694 | 695 | if(!tcp_acceptor_stopped) 696 | { 697 | ret = kthread_stop(tcp_server->accept_thread); 698 | if(!ret) 699 | pr_info(" *** mtp | tcp server acceptor thread" 700 | " stopped | network_server_exit *** \n"); 701 | } 702 | 703 | if(!tcp_listener_stopped) 704 | { 705 | ret = kthread_stop(tcp_server->thread); 706 | if(!ret) 707 | pr_info(" *** mtp | tcp server listening thread" 708 | " stopped | network_server_exit *** \n"); 709 | } 710 | 711 | 712 | if(tcp_server->listen_socket != NULL && !tcp_listener_stopped) 713 | { 714 | sock_release(tcp_server->listen_socket); 715 | tcp_server->listen_socket = NULL; 716 | } 717 | 718 | kfree(tcp_conn_handler); 719 | kfree(tcp_server); 720 | tcp_server = NULL; 721 | } 722 | 723 | pr_info(" *** mtp | network server module unloaded | " 724 | "network_server_exit *** \n"); 725 | } 726 | module_init(network_server_init) 727 | module_exit(network_server_exit) 728 | -------------------------------------------------------------------------------- /testing.c: -------------------------------------------------------------------------------- 1 | //simple 2 | //testing again 3 | -------------------------------------------------------------------------------- /todo.txt: -------------------------------------------------------------------------------- 1 | /** Done **/ 2 | 3 | struct socket *accept_socket 4 | 5 | Issue a call to sock_create(&accept_socket) 6 | every time when looking for a new connection. 7 | 8 | That means bring the sock_create() with the 9 | while(1) loop. 10 | 11 | This is necessary as, on exploring code of 12 | accept sys call (accept4) in net/socket.c, 13 | it was found that the syscall isuues a call 14 | to sock_alloc(), which returns a new socket 15 | every time. 16 | 17 | -------------------------------------------- 18 | 19 | Add a wait queue for connection handler 20 | thread, add it to accept_socket->sk->sk_wq->wait queue. 21 | The condition for which it waits should be, 22 | !skb_queue_empty(&accept_socket->sk->sk_receive_queue), 23 | i.e. something (msg) should be received in the 24 | sk_receive_queue of the sock struct associated with the 25 | accept_socket socket for this connection. 26 | 27 | /** Done **/ 28 | 29 | 30 | 31 | --------------------------------------------------------------------------------