1 files changed, 156 insertions, 0 deletions
diff --git a/web/server/h2o/libh2o/lib/handler/throttle_resp.c b/web/server/h2o/libh2o/lib/handler/throttle_resp.c
new file mode 100644
index 00000000..a0028b50
--- /dev/null
+++ b/web/server/h2o/libh2o/lib/handler/throttle_resp.c
@@ -0,0 +1,156 @@
+/*
+ * Copyright (c) 2016 Justin Zhu
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+#include <stdlib.h>
+#include "h2o.h"
+
+#ifndef HUNDRED_MS
+#define HUNDRED_MS 100
+#endif
+
+#ifndef ONE_SECOND
+#define ONE_SECOND 1000
+#endif
+
+typedef H2O_VECTOR(h2o_iovec_t) iovec_vector_t;
+
+typedef struct st_throttle_resp_t {
+    h2o_ostream_t super;
+    h2o_timeout_entry_t timeout_entry;
+    int64_t tokens;
+    size_t token_inc;
+    h2o_context_t *ctx;
+    h2o_req_t *req;
+    struct {
+        iovec_vector_t bufs;
+        h2o_send_state_t stream_state;
+    } state;
+} throttle_resp_t;
+
+static void real_send(throttle_resp_t *self)
+{
+    /* a really simple token bucket implementation */
+    assert(self->tokens > 0);
+    size_t i, token_consume;
+
+    token_consume = 0;
+
+    for (i = 0; i < self->state.bufs.size; i++) {
+        token_consume += self->state.bufs.entries[i].len;
+    }
+
+    self->tokens -= token_consume;
+
+    h2o_ostream_send_next(&self->super, self->req, self->state.bufs.entries, self->state.bufs.size, self->state.stream_state);
+    if (!h2o_send_state_is_in_progress(self->state.stream_state))
+        h2o_timeout_unlink(&self->timeout_entry);
+}
+
+static void add_token(h2o_timeout_entry_t *entry)
+{
+    throttle_resp_t *self = H2O_STRUCT_FROM_MEMBER(throttle_resp_t, timeout_entry, entry);
+
+    h2o_timeout_link(self->ctx->loop, &self->ctx->hundred_ms_timeout, &self->timeout_entry);
+    self->tokens += self->token_inc;
+
+    if (self->tokens > 0)
+        real_send(self);
+}
+
+static void on_send(h2o_ostream_t *_self, h2o_req_t *req, h2o_iovec_t *inbufs, size_t inbufcnt, h2o_send_state_t state)
+{
+    throttle_resp_t *self = (void *)_self;
+    size_t i;
+
+    /* I don't know if this is a proper way. */
+    h2o_vector_reserve(&req->pool, &self->state.bufs, inbufcnt);
+    /* start to save state */
+    for (i = 0; i < inbufcnt; ++i) {
+        self->state.bufs.entries[i] = inbufs[i];
+    }
+    self->state.bufs.size = inbufcnt;
+    self->state.stream_state = state;
+
+    /* if there's token, we try to send */
+    if (self->tokens > 0)
+        real_send(self);
+}
+
+static void on_stop(h2o_ostream_t *_self, h2o_req_t *req)
+{
+    throttle_resp_t *self = (void *)_self;
+    if (h2o_timeout_is_linked(&self->timeout_entry)) {
+        h2o_timeout_unlink(&self->timeout_entry);
+    }
+}
+
+static void on_setup_ostream(h2o_filter_t *self, h2o_req_t *req, h2o_ostream_t **slot)
+{
+    throttle_resp_t *throttle;
+    h2o_iovec_t traffic_header_value;
+    size_t traffic_limit;
+
+    if (req->res.status != 200)
+        goto Next;
+    if (h2o_memis(req->input.method.base, req->input.method.len, H2O_STRLIT("HEAD")))
+        goto Next;
+
+    ssize_t xt_index;
+    if ((xt_index = h2o_find_header(&req->res.headers, H2O_TOKEN_X_TRAFFIC, -1)) == -1)
+        goto Next;
+
+    traffic_header_value = req->res.headers.entries[xt_index].value;
+    char *buf = traffic_header_value.base;
+
+    if (H2O_UNLIKELY((traffic_limit = h2o_strtosizefwd(&buf, traffic_header_value.len)) == SIZE_MAX))
+        goto Next;
+
+    throttle = (void *)h2o_add_ostream(req, sizeof(throttle_resp_t), slot);
+
+    /* calculate the token increment per 100ms */
+    throttle->token_inc = traffic_limit * HUNDRED_MS / ONE_SECOND;
+    if (req->preferred_chunk_size > throttle->token_inc)
+        req->preferred_chunk_size = throttle->token_inc;
+
+    h2o_delete_header(&req->res.headers, xt_index);
+
+    throttle->super.do_send = on_send;
+    throttle->super.stop = on_stop;
+    throttle->ctx = req->conn->ctx;
+    throttle->req = req;
+    throttle->state.bufs.capacity = 0;
+    throttle->state.bufs.size = 0;
+    throttle->timeout_entry = (h2o_timeout_entry_t){0};
+    throttle->timeout_entry.cb = add_token;
+    throttle->tokens = throttle->token_inc;
+    slot = &throttle->super.next;
+
+    h2o_timeout_link(throttle->ctx->loop, &throttle->ctx->hundred_ms_timeout, &throttle->timeout_entry);
+
+Next:
+    h2o_setup_next_ostream(req, slot);
+}
+
+void h2o_throttle_resp_register(h2o_pathconf_t *pathconf)
+{
+    h2o_filter_t *self = h2o_create_filter(pathconf, sizeof(*self));
+    self->on_setup_ostream = on_setup_ostream;
+}