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      1 /*
      2  * xfrd-tcp.h - XFR (transfer) Daemon TCP system header file. Manages tcp conn.
      3  *
      4  * Copyright (c) 2001-2006, NLnet Labs. All rights reserved.
      5  *
      6  * See LICENSE for the license.
      7  *
      8  */
      9 
     10 #ifndef XFRD_TCP_H
     11 #define XFRD_TCP_H
     12 
     13 #include "xfrd.h"
     14 #ifdef HAVE_TLS_1_3
     15 #include <openssl/ssl.h>
     16 #endif
     17 
     18 
     19 struct buffer;
     20 struct xfrd_zone;
     21 struct xfrd_soa;
     22 struct xfrd_state;
     23 struct region;
     24 struct dname;
     25 struct acl_options;
     26 
     27 struct xfrd_tcp_pipeline;
     28 typedef struct xfrd_tcp xfrd_tcp_type;
     29 typedef struct xfrd_tcp_set xfrd_tcp_set_type;
     30 /*
     31  * A set of xfrd tcp connections.
     32  */
     33 struct xfrd_tcp_set {
     34 	/* tcp connections, array, each has packet and read/wr state */
     35 	struct xfrd_tcp_pipeline **tcp_state;
     36 	/* max number of tcp connections, size of tcp_state array */
     37 	int tcp_max;
     38 	/* max number of simultaneous connections on a tcp_pipeline */
     39 	int tcp_pipeline;
     40 	/* number of TCP connections in use. */
     41 	int tcp_count;
     42 	/* TCP timeout. */
     43 	int tcp_timeout;
     44 	/* rbtree with pipelines sorted by master */
     45 	rbtree_type* pipetree;
     46 #ifdef HAVE_TLS_1_3
     47 	/* XoT: SSL context */
     48 	SSL_CTX* ssl_ctx;
     49 #endif
     50 	/* double linked list of zones waiting for a TCP connection */
     51 	struct xfrd_zone *tcp_waiting_first, *tcp_waiting_last;
     52 };
     53 
     54 /*
     55  * Structure to keep track of an open tcp connection
     56  * The xfrd tcp connection is used to first make a request
     57  * Then to receive the answer packet(s).
     58  */
     59 struct xfrd_tcp {
     60 	/* tcp connection state */
     61 	/* state: reading or writing */
     62 	uint8_t is_reading;
     63 
     64 	/* how many bytes have been read/written - total,
     65 	   incl. tcp length bytes */
     66 	uint32_t total_bytes;
     67 
     68 	/* msg len bytes */
     69 	uint16_t msglen;
     70 
     71 	/* fd of connection. -1 means unconnected */
     72 	int fd;
     73 
     74 	/* packet buffer of connection */
     75 	struct buffer* packet;
     76 };
     77 
     78 /* use illegal pointer value to denote skipped ID number.
     79  * if this does not work, we can allocate with malloc */
     80 #define TCP_NULL_SKIP ((struct xfrd_zone*)-1)
     81 
     82 /**
     83  * The per-id zone pointers, with TCP_NULL_SKIP or a zone pointer for the
     84  * ID value.
     85  */
     86 struct xfrd_tcp_pipeline_id {
     87 	/** rbtree node as first member, this is the key. */
     88 	rbnode_type node;
     89 	/** the ID of this member */
     90 	uint16_t id;
     91 	/** zone pointer or TCP_NULL_SKIP */
     92 	struct xfrd_zone* zone;
     93 	/** next free in free list */
     94 	struct xfrd_tcp_pipeline_id* next_free;
     95 };
     96 
     97 /**
     98  * The tcp pipeline key structure. By ip_len, ip, num_unused and unique by
     99  * pointer value.
    100  */
    101 struct xfrd_tcp_pipeline_key {
    102 	/* the rbtree node, sorted by IP and nr of unused queries */
    103 	rbnode_type node;
    104 	/* destination IP address */
    105 #ifdef INET6
    106 	struct sockaddr_storage ip;
    107 #else
    108 	struct sockaddr_in ip;
    109 #endif /* INET6 */
    110 	socklen_t ip_len;
    111 	/* number of unused IDs.  used IDs are waiting to send their query,
    112 	 * or have been sent but not not all answer packets have been received.
    113 	 * Sorted by num_unused, so a lookup smaller-equal for 65536 finds the
    114 	 * connection to that master that has the most free IDs. */
    115 	int num_unused;
    116 	/* number of skip-set IDs (these are 'in-use') */
    117 	int num_skip;
    118 };
    119 
    120 /**
    121  * Structure to keep track of a pipelined set of queries on
    122  * an open tcp connection.  The queries may be answered with
    123  * interleaved answer packets, the ID number disambiguates.
    124  * Sorted by the master IP address so you can use lookup with
    125  * smaller-or-equal to find the tcp connection most suitable.
    126  */
    127 struct xfrd_tcp_pipeline {
    128 	/* the key information for the tcp pipeline, in its own
    129 	 * struct so it can be referenced on its own for comparison funcs */
    130 	struct xfrd_tcp_pipeline_key key;
    131 
    132 	int handler_added;
    133 	/* the event handler for this pipe (it'll disambiguate by ID) */
    134 	struct event handler;
    135 
    136 	/* the tcp connection to use for reading */
    137 	struct xfrd_tcp* tcp_r;
    138 	/* the tcp connection to use for writing, if it is done successfully,
    139 	 * then the first zone from the sendlist can be removed. */
    140 	struct xfrd_tcp* tcp_w;
    141 	/* once a byte has been written, handshake complete */
    142 	int connection_established;
    143 #ifdef HAVE_TLS_1_3
    144 	/* XoT: SSL object */
    145 	SSL *ssl;
    146 	/* XoT: if SSL handshake is not done, handshake_want indicates the
    147 	 * last error. This may be SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE
    148 	 * when the handshake is still in progress.
    149 	 */
    150 	int  handshake_want;
    151 	/* XoT: 1 if the SSL handshake has succeeded, 0 otherwise */
    152 	int  handshake_done;
    153 #endif
    154 
    155 	/* list of queries that want to send, first to get write event,
    156 	 * if NULL, no write event interest */
    157 	struct xfrd_zone* tcp_send_first, *tcp_send_last;
    158 
    159 	/* size of the id and unused arrays. */
    160 	int pipe_num;
    161 	/* list of free xfrd_tcp_pipeline_id nodes, these are not in the
    162 	 * zone_per_id tree. preallocated at pipe_num amount. */
    163 	struct xfrd_tcp_pipeline_id* pipe_id_free_list;
    164 	/* The xfrd_zone pointers, per id number.
    165 	 * The key is struct xfrd_tcp_pipeline_id.
    166 	 * per-ID number the queries that have this ID number, every
    167 	 * query owns one ID numbers (until it is done). NULL: unused
    168 	 * When a query is done but not all answer-packets have been
    169 	 * consumed for that ID number, the rest is skipped, this
    170 	 * is denoted with the pointer-value TCP_NULL_SKIP, the ids that
    171 	 * are skipped are not on the unused list.  They may be
    172 	 * removed once the last answer packet is skipped.
    173 	 * pipe_num-num_unused values are in the tree (either
    174 	 * a zone pointer or SKIP) */
    175 	rbtree_type* zone_per_id;
    176 	/* Array of uint16_t, with ID values.
    177 	 * unused ID numbers; the first part of the array contains the IDs */
    178 	uint16_t* unused;
    179 };
    180 
    181 /* create set of tcp connections */
    182 struct xfrd_tcp_set* xfrd_tcp_set_create(struct region* region, const char *tls_cert_bundle, int tcp_max, int tcp_pipeline);
    183 
    184 /* init tcp state */
    185 struct xfrd_tcp* xfrd_tcp_create(struct region* region, size_t bufsize);
    186 /* obtain tcp connection for a zone (or wait) */
    187 void xfrd_tcp_obtain(struct xfrd_tcp_set* set, struct xfrd_zone* zone);
    188 /* release tcp connection for a zone (starts waiting) */
    189 void xfrd_tcp_release(struct xfrd_tcp_set* set, struct xfrd_zone* zone);
    190 /* release tcp pipe entirely (does not stop the zones inside it) */
    191 void xfrd_tcp_pipe_release(struct xfrd_tcp_set* set,
    192 	struct xfrd_tcp_pipeline* tp, int conn);
    193 /* use tcp connection to start xfr */
    194 void xfrd_tcp_setup_write_packet(struct xfrd_tcp_pipeline* tp,
    195 	struct xfrd_zone* zone);
    196 /* initialize tcp_state for a zone. Opens the connection. true on success.*/
    197 int xfrd_tcp_open(struct xfrd_tcp_set* set, struct xfrd_tcp_pipeline* tp,
    198 	struct xfrd_zone* zone);
    199 /* read data from tcp, maybe partial read */
    200 void xfrd_tcp_read(struct xfrd_tcp_pipeline* tp);
    201 /* write data to tcp, maybe a partial write */
    202 void xfrd_tcp_write(struct xfrd_tcp_pipeline* tp, struct xfrd_zone* zone);
    203 /* handle tcp pipe events */
    204 void xfrd_handle_tcp_pipe(int fd, short event, void* arg);
    205 
    206 /*
    207  * Read from a stream connection (size16)+packet into buffer.
    208  * returns value is
    209  *	-1 on error.
    210  *	0 on short read, call back later.
    211  *	1 on completed read.
    212  * On first call, make sure total_bytes = 0, msglen=0, buffer_clear().
    213  * and the packet and fd need to be set.
    214  */
    215 int conn_read(struct xfrd_tcp* conn);
    216 /*
    217  * Write to a stream connection (size16)+packet.
    218  * return value is
    219  * -1 on error. 0 on short write, call back later. 1 completed write.
    220  * On first call, make sure total_bytes=0, msglen=buffer_limit(),
    221  * buffer_flipped(). packet and fd need to be set.
    222  */
    223 int conn_write(struct xfrd_tcp* conn);
    224 
    225 /* setup DNS packet for a query of this type */
    226 void xfrd_setup_packet(struct buffer* packet,
    227         uint16_t type, uint16_t klass, const struct dname* dname, uint16_t qid,
    228 	int* apex_compress);
    229 /* write soa in network format to the packet buffer */
    230 void xfrd_write_soa_buffer(struct buffer* packet,
    231         const struct dname* apex, struct xfrd_soa* soa, int apex_compress);
    232 /* use acl address to setup sockaddr struct, returns length of addr. */
    233 socklen_t xfrd_acl_sockaddr_to(struct acl_options* acl,
    234 #ifdef INET6
    235 	struct sockaddr_storage *to);
    236 #else
    237 	struct sockaddr_in *to);
    238 #endif /* INET6 */
    239 
    240 socklen_t xfrd_acl_sockaddr_frm(struct acl_options* acl,
    241 #ifdef INET6
    242 	struct sockaddr_storage *frm);
    243 #else
    244 	struct sockaddr_in *frm);
    245 #endif /* INET6 */
    246 
    247 /* create pipeline tcp structure */
    248 struct xfrd_tcp_pipeline* xfrd_tcp_pipeline_create(region_type* region,
    249 	int tcp_pipeline);
    250 /* pick num uint16_t values, from 0..max-1, store in array */
    251 void pick_id_values(uint16_t* array, int num, int max);
    252 
    253 #ifdef HAVE_SSL
    254 void get_cert_info(SSL* ssl, region_type* region, char** cert_serial,
    255 	char** key_id, char** cert_algorithm, char** tls_version);
    256 #endif
    257 
    258 #endif /* XFRD_TCP_H */
    259