Provided by: trafficserver-dev_9.2.3+ds-1+deb12u1build4_amd64 bug

NAME

       TSClientProtocolStack - TSClientProtocolStack API function

SYNOPSIS

          #include <ts/ts.h>

       TSReturnCode TSHttpTxnClientProtocolStackGet(TSHttpTxn txnp, int count, char const **result, int *actual)

       TSReturnCode TSHttpTxnServerProtocolStackGet(TSHttpTxn txnp, int count, const char **result, int *actual)

       TSReturnCode TSHttpSsnClientProtocolStackGet(TSHttpSsn ssnp, int count, char const **result, int *actual)

       char const *TSHttpTxnClientProtocolStackContains(TSHttpTxn txnp)

       const char *TSHttpTxnServerProtocolStackContains(TSHttpTxn txnp, char const *tag)

       char const *TSHttpSsnClientProtocolStackContains(TSHttpSsn ssnp)

       char const *TSNormalizedProtocolTag(char const *tag)

       char const *TSRegisterProtocolTag(char const *tag)

DESCRIPTION

       These functions are used to explore the protocol stack of either the client (user agent) or origin server
       connection     to     Traffic     Server.    The    functions    TSHttpTxnClientProtocolStackGet()    and
       TSHttpSsnClientProtocolStackGet() can be used to retrieve the entire protocol stack for  the  user  agent
       connection.  The  TSHttpTxnServerProtocolStackGet() can be used to retrieve the entire protocol stack for
       the          origin          server          connection.          TSHttpTxnClientProtocolStackContains(),
       TSHttpSsnClientProtocolStackContains(),  and  TSHttpTxnServerProtocolStackContains()   will  check  for a
       specific protocol tag being present in the stack.

       Each protocol is represented by tag which is a null terminated string. A particular tag  will  always  be
       returned as the same character pointer and so protocols can be reliably checked with pointer comparisons.
       TSNormalizedProtocolTag()  will  return this character pointer for a specific tag. A return value of NULL
       indicates the provided tag is not registered as a known protocol tag.  TSRegisterProtocolTag()  registers
       the  tag  and then returns its normalized value. This is useful for plugins that provide custom protocols
       for user agents.

       The protocols are ordered from higher level protocols to  the  lower  level  ones  on  which  the  higher
       operate.    For    instance    a    stack    might    look    like    "http/1.1,tls/1.2,tcp,ipv4".    For
       TSHttpTxnClientProtocolStackGet(),                 TSHttpSsnClientProtocolStackGet(),                 and
       TSHttpTxnServerProtocolStackGet()  these  values  are  placed  in  the array result. count is the maximum
       number of elements of result that may be modified by the function call. If actual is not  NULL  then  the
       actual  number  of  elements  in the protocol stack will be returned. If this is equal or less than count
       then all elements were returned. If it is larger then some layers were omitted from result. If  the  full
       stack  is  required  actual can be used to resize result to be sufficient to hold all of the elements and
       the function called again with updated count and result. In practice the maximum number  of  elements  is
       almost  certain  to  be less than 10 which therefore should suffice. These functions return TS_SUCCESS on
       success and TS_ERROR on failure which should only occur if txnp or ssnp are invalid.

       The       TSHttpTxnClientProtocolStackContains(),       TSHttpSsnClientProtocolStackContains(),       and
       TSHttpTxnServerProtocolStackContains()  functions are provided for the convenience when only the presence
       of a protocol is of interest, not its location or the presence of other protocols. These functions return
       NULL if the protocol tag is not present, and a pointer to the  normalized  tag  if  it  is  present.  The
       strings  are  matched with an anchor prefix search, as with debug tags. For instance if tag is "tls" then
       it will match "tls/1.2" or "tls/1.3". This makes  checking  for  TLS  or  IP  more  convenient.  If  more
       precision is required the entire protocol stack can be retrieved and processed more thoroughly.

       The protocol tags defined by Traffic Server.
                                               ────────────────────────
                                                 Protocol    Tag
                                               ────────────────────────
                                                 HTTP/1.1    http/1.1
                                               ────────────────────────
                                                 HTTP/1.0    http/1.0
                                               ────────────────────────
                                                 HTTP/2      h2
                                               ────────────────────────
                                                 WebSocket   ws
                                               ────────────────────────
                                                 TLS 1.3     tls/1.3
                                               ────────────────────────
                                                 TLS 1.2     tls/1.2
                                               ────────────────────────
                                                 TLS 1.1     tls/1.1
                                               ────────────────────────
                                                 TLS 1.0     tls/1.0
                                               ────────────────────────
                                                 TCP         tcp
                                               ────────────────────────
                                                 UDP         udp
                                               ────────────────────────
                                                 IPv4        ipv4
                                               ────────────────────────
                                                 IPv6        ipv6
                                               ────────────────────────
                                                 QUIC        quic
                                               ┌───────────┬──────────┐
                                               │           │          │
   Examples                                    │           │          │
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