skb_mpls_dec_ttl(9)

💖 skb_mpls_dec_ttl 💖

okay so bestie, welcome to the skb_mpls_dec_ttl(9) page — it's a Kernel API Manual situation, and honestly it's a short one so we can absolutely get through it together 🫶

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✨ NAME ✨

skb_mpls_dec_ttl — decrement the TTL of the outermost MPLS header 💅

no bc that's literally it, that's the whole gig, and it ate 🔥

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🎀 SYNOPSIS 🎀

int skb_mpls_dec_ttl (struct sk_buff *skb );

she takes one argument, she returns an int, she does not elaborate 💁‍♀️

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🌸 ARGUMENTS 🌸

• skb — buffer. that's it. that's the description. the buffer itself. the whole girl 🦋

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💜 DESCRIPTION 💜

okay so here's the vibe check: this function expects skb->data to be sitting at the mac header. iykyk, that's the positioning she needs before she does her little TTL decrement on the outermost MPLS header ✨

and then the return situation, which is very simple and very iconic:

• returns 0 on success 🎉
• returns -errno otherwise 😭

periodt. no cap, that's the entire description, don't come for her for being brief, she's a specialist 💅

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🌈 SEE ALSO 🌈

the kernel file lives at ./net/core/skbuff.c, and listen, the friend group is HUGE — here's every single one of them, all in (9) form, no one left behind 👑

drop_reasons_register_subsys(9), drop_reasons_unregister_subsys(9), skb_panic(9), napi_skb_cache_get_bulk(9), __build_skb(9), build_skb_around(9), __napi_build_skb(9), napi_build_skb(9), __alloc_skb(9), __netdev_alloc_skb(9), napi_alloc_skb(9), skb_pp_cow_data(9), skb_pp_frag_ref(9), __kfree_skb(9), sk_skb_reason_drop(9), skb_tx_error(9), consume_skb(9), __consume_stateless_skb(9), napi_consume_skb(9), alloc_skb_for_msg(9), skb_morph(9), skb_copy_ubufs(9), skb_clone(9), skb_copy(9), __pskb_copy_fclone(9), pskb_expand_head(9), skb_expand_head(9), skb_copy_expand(9), __skb_pad(9), pskb_put(9), skb_put(9), skb_push(9), skb_pull(9), skb_pull_data(9), skb_trim(9), __pskb_pull_tail(9), skb_copy_bits(9), skb_store_bits(9), skb_zerocopy(9), skb_dequeue(9), skb_dequeue_tail(9), skb_queue_purge_reason(9), skb_rbtree_purge(9), skb_queue_head(9), skb_queue_tail(9), skb_unlink(9), skb_append(9), skb_split(9), skb_shift(9), skb_prepare_seq_read(9), skb_seq_read(9), skb_abort_seq_read(9), skb_copy_seq_read(9), skb_find_text(9), skb_pull_rcsum(9), skb_segment(9), skb_to_sgvec(9), skb_cow_data(9), skb_clone_sk(9), skb_partial_csum_set(9), skb_checksum_setup(9), skb_checksum_maybe_trim(9), skb_checksum_trimmed(9), skb_try_coalesce(9), skb_scrub_packet(9), skb_eth_pop(9), skb_eth_push(9), skb_mpls_push(9), skb_mpls_pop(9), skb_mpls_update_lse(9), alloc_skb_with_frags(9), skb_condense(9), __skb_ext_alloc(9), __skb_ext_set(9), skb_ext_add(9), skb_attempt_defer_free(9), skb_splice_from_iter(9)

like I said. huge friend group. all iconic, all linked, all accounted for 💖

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🧚 sign-off 🧚

this page is served fresh from ./net/core, dated October 2026, and it's skb_mpls_dec_ttl(9) all the way down, bestie 💜 go decrement that TTL, you're gonna slay ⭐