---
name: "TSVConnProtocol"
section: "3ts"
platform: "linux"
package: "trafficserver-dev"
version: "9.2.5+ds-0+deb12u4"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/TSVConnProtocol"
---

# TSVConnProtocol(3ts)

TSVConnProtocol API function

## NAME

TSVConnProtocolEnable/Disable - TSVConnProtocol API function

## SYNOPSIS

```
#include <ts/ts.h>
```

- ***TSReturnCode* TSVConnProtocolEnable(*TSVConn* vconn, const char \*protocol)**

  - ***TSReturnCode* TSVConnProtocolDisable(*TSVConn* vconn, const char \*protocol)**

  ## DESCRIPTION

*TSVConnProtocolEnable()* will enable the protocol specified by *protocol* to be advertised in the TLS protocol negotiation.

Similarly, *TSVConnProtocolDisable()* will remove the protocol specified by *protocol* from the TLS protocol negotiation.

To be effective, these calls must be made from the early TLS negotiation hooks like *TS\_SSL\_CLIENT\_HELLO\_HOOK* or *TS\_SSL\_SERVERNAME\_HOOK*.

## EXAMPLES

The example below is excerpted from *example/plugins/c-api/disable\_http2/disable\_http2.cc* in the Traffic Server source distribution. It shows how the *TSVConnProtocolDisable()* function can be used in a plugin called from the *TS\_SSL\_SERVERNAME\_HOOK*.

```
int
CB_SNI(TSCont contp, TSEvent, void *cb_data)
{
  auto vc                  = static_cast<TSVConn>(cb_data);
  TSSslConnection ssl_conn = TSVConnSslConnectionGet(vc);
  auto *ssl                = reinterpret_cast<SSL *>(ssl_conn);
  char const *sni          = SSL_get_servername(ssl, TLSEXT_NAMETYPE_host_name);
  if (sni) {
    if (Domains.find(sni) != Domains.end()) {
      TSDebug(PLUGIN_NAME, "Disable H2 for SNI=%s", sni);
      TSVConnProtocolDisable(vc, TS_ALPN_PROTOCOL_HTTP_2_0);
    }
  }
```

## COPYRIGHT

2026, dev@trafficserver.apache.org